--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/BatchCompilerTest.java	
+++ a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/BatchCompilerTest.java	
@@ -1799,6 +1799,7 @@ 
 			"		<argument value=\"---OUTPUT_DIR_PLACEHOLDER---\"/>\n" + 
 			"	</command_line>\n" + 
 			"	<options>\n" + 
+			"		<option key=\"org.eclipse.jdt.core.compiler.annotation.nullanalysis\" value=\"disabled\"/>\n" +
 			"		<option key=\"org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode\" value=\"disabled\"/>\n" + 
 			"		<option key=\"org.eclipse.jdt.core.compiler.codegen.targetPlatform\" value=\"1.5\"/>\n" + 
 			"		<option key=\"org.eclipse.jdt.core.compiler.codegen.unusedLocal\" value=\"optimize out\"/>\n" + 
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/CompilerInvocationTests.java	
+++ a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/CompilerInvocationTests.java	
@@ -380,6 +380,7 @@ 
 		expectedProblemAttributes.put("CannotDefineStaticInitializerInLocalType", new ProblemAttributes(CategorizedProblem.CAT_INTERNAL));
 		expectedProblemAttributes.put("CannotExtendEnum", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("CannotHideAnInstanceMethodWithAStaticMethod", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
+		expectedProblemAttributes.put("CannotImplementIncompatibleNullness", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("CannotImportPackage", new ProblemAttributes(CategorizedProblem.CAT_IMPORT));
 		expectedProblemAttributes.put("CannotInferElidedTypes", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("CannotInvokeSuperConstructorInEnum", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
@@ -472,6 +473,7 @@ 
 		expectedProblemAttributes.put("IllegalAccessFromTypeVariable", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("IllegalCast", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("IllegalClassLiteralForTypeVariable", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
+		expectedProblemAttributes.put("IllegalDefinitionToNonNullParameter", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("IllegalDimension", new ProblemAttributes(CategorizedProblem.CAT_INTERNAL));
 		expectedProblemAttributes.put("IllegalEnclosingInstanceSpecification", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("IllegalExtendedDimensions", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
@@ -506,6 +508,8 @@ 
 		expectedProblemAttributes.put("IllegalPrimitiveOrArrayTypeForEnclosingInstance", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("IllegalQualifiedEnumConstantLabel", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
 		expectedProblemAttributes.put("IllegalQualifiedParameterizedTypeAllocation", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
+		expectedProblemAttributes.put("IllegalReturnNullityRedefinition", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("IllegalRedefinitionToNonNullParameter", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("IllegalStaticModifierForMemberType", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("IllegalTypeVariableSuperReference", new ProblemAttributes(CategorizedProblem.CAT_INTERNAL));
 		expectedProblemAttributes.put("IllegalUnderscorePosition", new ProblemAttributes(CategorizedProblem.CAT_SYNTAX));
@@ -690,6 +694,7 @@ 
 		expectedProblemAttributes.put("MissingEnclosingInstanceForConstructorCall", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("MissingEnumConstantCase", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("MissingOverrideAnnotation", new ProblemAttributes(CategorizedProblem.CAT_CODE_STYLE));
+		expectedProblemAttributes.put("MissingNullAnnotationType", new ProblemAttributes(CategorizedProblem.CAT_BUILDPATH));
 		expectedProblemAttributes.put("MissingOverrideAnnotationForInterfaceMethodImplementation", new ProblemAttributes(CategorizedProblem.CAT_CODE_STYLE));
 		expectedProblemAttributes.put("MissingReturnType", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("MissingSemiColon", new ProblemAttributes(CategorizedProblem.CAT_SYNTAX));
@@ -729,6 +734,7 @@ 
 		expectedProblemAttributes.put("NotVisibleField", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
 		expectedProblemAttributes.put("NotVisibleMethod", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
 		expectedProblemAttributes.put("NotVisibleType", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
+		expectedProblemAttributes.put("NullAnnotationNameMustBeQualified", new ProblemAttributes(CategorizedProblem.CAT_BUILDPATH));
 		expectedProblemAttributes.put("NullLocalVariableComparisonYieldsFalse", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("NullLocalVariableInstanceofYieldsFalse", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("NullLocalVariableReference", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
@@ -745,6 +751,8 @@ 
 		expectedProblemAttributes.put("PackageCollidesWithType", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("PackageIsNotExpectedPackage", new ProblemAttributes(CategorizedProblem.CAT_INTERNAL));
 		expectedProblemAttributes.put("ParameterAssignment", new ProblemAttributes(CategorizedProblem.CAT_CODE_STYLE));
+		expectedProblemAttributes.put("ParameterLackingNonNullAnnotation", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("ParameterLackingNullableAnnotation", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("ParameterMismatch", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
 		expectedProblemAttributes.put("ParameterizedConstructorArgumentTypeMismatch", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("ParameterizedMethodArgumentTypeMismatch", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
@@ -771,6 +779,7 @@ 
 		expectedProblemAttributes.put("PotentiallyUnclosedCloseable", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("PotentiallyUnclosedCloseableAtExit", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("PotentialNullLocalVariableReference", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("PotentialNullMessageSendReference", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("PublicClassMustMatchFileName", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("RawMemberTypeCannotBeParameterized", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("RawTypeReference", new ProblemAttributes(CategorizedProblem.CAT_UNCHECKED_RAW));
@@ -779,10 +788,15 @@ 
 		expectedProblemAttributes.put("RedefinedLocal", new ProblemAttributes(CategorizedProblem.CAT_INTERNAL));
 		expectedProblemAttributes.put("RedundantSpecificationOfTypeArguments", new ProblemAttributes(CategorizedProblem.CAT_UNNECESSARY_CODE));
 		expectedProblemAttributes.put("RedundantLocalVariableNullAssignment", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("RedundantNullAnnotation", new ProblemAttributes(CategorizedProblem.CAT_UNNECESSARY_CODE));
 		expectedProblemAttributes.put("RedundantNullCheckOnNonNullLocalVariable", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("RedundantNullCheckOnNonNullMessageSend", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("RedundantNullCheckOnNullLocalVariable", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("RedundantSuperinterface", new ProblemAttributes(CategorizedProblem.CAT_UNNECESSARY_CODE));
 		expectedProblemAttributes.put("ReferenceToForwardField", new ProblemAttributes(CategorizedProblem.CAT_MEMBER));
+		expectedProblemAttributes.put("RequiredNonNullButProvidedNull", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("RequiredNonNullButProvidedPotentialNull", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
+		expectedProblemAttributes.put("RequiredNonNullButProvidedUnknown", new ProblemAttributes(CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM));
 		expectedProblemAttributes.put("ReferenceToForwardTypeVariable", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("ResourceHasToImplementAutoCloseable", new ProblemAttributes(CategorizedProblem.CAT_TYPE));
 		expectedProblemAttributes.put("ReturnTypeAmbiguous", DEPRECATED);
--- /dev/null	
+++ a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullAnnotationTest.java	
@@ -0,0 +1,2143 @@ 
+/*******************************************************************************
+ * Copyright (c) 2010, 2011 GK Software AG and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Stephan Herrmann - initial API and implementation 
+ *******************************************************************************/
+package org.eclipse.jdt.core.tests.compiler.regression;
+
+
+import java.io.File;
+import java.util.Map;
+
+import junit.framework.Test;
+
+import org.eclipse.core.runtime.FileLocator;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
+
+public class NullAnnotationTest extends AbstractComparableTest {
+
+// class libraries including our default null annotation types:
+String[] LIBS;
+
+// names and content of custom annotations used in a few tests:
+private static final String CUSTOM_NONNULL_NAME = "org/foo/NonNull.java";
+private static final String CUSTOM_NONNULL_CONTENT = 
+	"package org.foo;\n" +
+	"import static java.lang.annotation.ElementType.*;\n" + 
+	"import java.lang.annotation.*;\n" + 
+	"@Retention(RetentionPolicy.CLASS)\n" + 
+	"@Target({METHOD,PARAMETER,LOCAL_VARIABLE})\n" + 
+	"public @interface NonNull {\n" + 
+	"}\n";
+private static final String CUSTOM_NULLABLE_NAME = "org/foo/Nullable.java";
+private static final String CUSTOM_NULLABLE_CONTENT = "package org.foo;\n" +
+	"import static java.lang.annotation.ElementType.*;\n" + 
+	"import java.lang.annotation.*;\n" +
+	"@Retention(RetentionPolicy.CLASS)\n" + 
+	"@Target({METHOD,PARAMETER,LOCAL_VARIABLE})\n" + 
+	"public @interface Nullable {\n" + 
+	"}\n";
+
+public NullAnnotationTest(String name) {
+	super(name);
+}
+
+// Static initializer to specify tests subset using TESTS_* static variables
+// All specified tests which do not belong to the class are skipped...
+static {
+//		TESTS_NAMES = new String[] { "test_nonnull_var_in_constrol_structure_3" };
+//		TESTS_NUMBERS = new int[] { 561 };
+//		TESTS_RANGE = new int[] { 1, 2049 };
+}
+
+public static Test suite() {
+	return buildComparableTestSuite(testClass());
+}
+
+public static Class testClass() {
+	return NullAnnotationTest.class;
+}
+
+protected void setUp() throws Exception {
+	super.setUp();
+	if (this.LIBS == null) {
+		String[] defaultLibs = getDefaultClassPaths();
+		int len = defaultLibs.length;
+		this.LIBS = new String[len+1];
+		System.arraycopy(defaultLibs, 0, this.LIBS, 0, len);
+		File bundleFile = FileLocator.getBundleFile(Platform.getBundle("org.eclipse.jdt.annotation.null"));
+		if (bundleFile.isDirectory())
+			this.LIBS[len] = bundleFile.getPath()+"/bin";
+		else
+			this.LIBS[len] = bundleFile.getPath();
+	}
+}
+// Conditionally augment problem detection settings
+static boolean setNullRelatedOptions = true;
+protected Map getCompilerOptions() {
+    Map defaultOptions = super.getCompilerOptions();
+    if (setNullRelatedOptions) {
+    	defaultOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	    defaultOptions.put(CompilerOptions.OPTION_ReportPotentialNullReference, CompilerOptions.ERROR);
+	    defaultOptions.put(CompilerOptions.OPTION_ReportRedundantNullCheck, CompilerOptions.ERROR);
+		defaultOptions.put(CompilerOptions.OPTION_ReportRawTypeReference, CompilerOptions.IGNORE);
+		defaultOptions.put(CompilerOptions.OPTION_IncludeNullInfoFromAsserts, CompilerOptions.ENABLED);
+		
+		defaultOptions.put(CompilerOptions.OPTION_ReportMissingOverrideAnnotationForInterfaceMethodImplementation, CompilerOptions.DISABLED);
+
+		// enable null annotations:
+		defaultOptions.put(CompilerOptions.OPTION_AnnotationBasedNullAnalysis, CompilerOptions.ENABLED);
+		// leave other new options at these defaults:
+//		defaultOptions.put(CompilerOptions.OPTION_ReportNullContractViolation, CompilerOptions.ERROR);
+//		defaultOptions.put(CompilerOptions.OPTION_ReportPotentialNullContractViolation, CompilerOptions.ERROR);
+//		defaultOptions.put(CompilerOptions.OPTION_ReportNullContractInsufficientInfo, CompilerOptions.WARNING);
+		
+//		defaultOptions.put(CompilerOptions.OPTION_NullableAnnotationName, "org.eclipse.jdt.annotation.Nullable");
+//		defaultOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.eclipse.jdt.annotation.NonNull");
+    }
+    return defaultOptions;
+}
+void runNegativeTestWithLibs(String[] testFiles, String expectedErrorLog) {
+	runNegativeTest(
+			testFiles,
+			expectedErrorLog,
+			this.LIBS,
+			false /*shouldFlush*/);
+}
+void runNegativeTestWithLibs(boolean shouldFlushOutputDirectory, String[] testFiles, Map customOptions, String expectedErrorLog) {
+	runNegativeTest(
+			shouldFlushOutputDirectory,
+			testFiles,
+			this.LIBS,
+			customOptions,
+			expectedErrorLog,
+			// runtime options
+		    JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
+}
+void runNegativeTestWithLibs(String[] testFiles, Map customOptions, String expectedErrorLog) {
+	runNegativeTestWithLibs(false /* flush output directory */,	testFiles, customOptions, expectedErrorLog);
+}
+void runConformTestWithLibs(String[] testFiles, Map customOptions, String expectedCompilerLog) {
+	runConformTestWithLibs(false /* flush output directory */, testFiles, customOptions, expectedCompilerLog);
+}
+void runConformTestWithLibs(boolean shouldFlushOutputDirectory, String[] testFiles, Map customOptions, String expectedCompilerLog) {
+	runConformTest(
+			shouldFlushOutputDirectory,
+			testFiles,
+			this.LIBS,
+			customOptions,
+			expectedCompilerLog,
+			"",/* expected output */
+			"",/* expected error */
+		    JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
+}
+void runConformTest(String[] testFiles, Map customOptions, String expectedOutputString) {
+	runConformTest(
+			testFiles, 
+			expectedOutputString, 
+			null /*classLibraries*/, 
+			true /*shouldFlushOutputDirectory*/,
+			null /*vmArguments*/, 
+			customOptions, 
+			null /*customRequestor*/);
+	
+}
+// a nullable argument is dereferenced without a check
+public void test_nullable_paramter_001() {
+	runNegativeTest(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    void foo(@Nullable Object o) {\n" +
+			  "        System.out.print(o.toString());\n" +
+			  "    }\n" +
+			  "}\n"},
+	    "----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	System.out.print(o.toString());\n" + 
+		"	                 ^\n" + 
+		"Potential null pointer access: The variable o may be null at this location\n" + 
+		"----------\n",
+		this.LIBS,
+		true /* shouldFlush*/);
+}
+
+// a null value is passed to a nullable argument
+public void test_nullable_paramter_002() {
+	runConformTest(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    void foo(@Nullable Object o) {\n" +
+			  "        // nop\n" +
+			  "    }\n" +
+			  "    void bar() {\n" +
+			  "        foo(null);\n" +
+			  "    }\n" +
+			  "}\n"},
+	    "",
+	    this.LIBS,
+	    false/*shouldFlush*/,
+	    null/*vmArgs*/);
+}
+
+// a non-null argument is checked for null
+public void test_nonnull_parameter_001() {
+	runNegativeTest(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    void foo(@NonNull Object o) {\n" +
+			  "        if (o != null)\n" +
+			  "              System.out.print(o.toString());\n" +
+			  "    }\n" +
+			  "}\n"},
+	    "----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	if (o != null)\n" + 
+		"	    ^\n" + 
+		"Redundant null check: The variable o cannot be null at this location\n" + 
+		"----------\n",
+		this.LIBS,
+		true /* shouldFlush*/);
+}
+// a non-null argument is dereferenced without a check
+public void test_nonnull_parameter_002() {
+	runConformTest(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    void foo(@NonNull Object o) {\n" +
+			  "        System.out.print(o.toString());\n" +
+			  "    }\n" +
+			  "    public static void main(String... args) {\n" +
+			  "        new X().foo(\"OK\");\n" +
+			  "    }\n" +
+			  "}\n"},
+	    "OK",
+	    this.LIBS,
+	    false/*shouldFlush*/,
+	    null/*vmArgs*/);
+}
+// passing null to nonnull parameter - many fields in enclosing class
+public void test_nonnull_parameter_003() {
+	runNegativeTest(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    int i00, i01, i02, i03, i04, i05, i06, i07, i08, i09;" +
+			  "    int i10, i11, i12, i13, i14, i15, i16, i17, i18, i19;" +
+			  "    int i20, i21, i22, i23, i24, i25, i26, i27, i28, i29;" +
+			  "    int i30, i31, i32, i33, i34, i35, i36, i37, i38, i39;" +
+			  "    int i40, i41, i42, i43, i44, i45, i46, i47, i48, i49;" +
+			  "    int i50, i51, i52, i53, i54, i55, i56, i57, i58, i59;" +
+			  "    int i60, i61, i62, i63, i64, i65, i66, i67, i68, i69;" +
+			  "    void foo(@NonNull Object o) {\n" +
+			  "        System.out.print(o.toString());\n" +
+			  "    }\n" +
+			  "    void bar() {\n" +
+			  "        foo(null);\n" +
+			  "    }\n" +
+			  "}\n"},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 7)\n" + 
+		"	foo(null);\n" + 
+		"	    ^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" + 
+		"----------\n",
+		this.LIBS,
+		true /* shouldFlush*/);
+}
+// passing potential null to nonnull parameter - target method is consumed from .class
+public void test_nonnull_parameter_004() {
+	runConformTestWithLibs(
+			new String[] {
+				"Lib.java",
+					"import org.eclipse.jdt.annotation.*;\n" +
+				"public class Lib {\n" +
+				"    void setObject(@NonNull Object o) { }\n" +
+				"}\n"
+			},
+			null /*customOptions*/,
+			"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			  "public class X {\n" +
+			  "    void bar(Lib l, boolean b) {\n" +
+			  "        Object o = null;\n" +
+			  "        if (b) o = new Object();\n" +
+			  "        l.setObject(o);\n" +
+			  "    }\n" +
+			  "}\n"},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 5)\n" + 
+		"	l.setObject(o);\n" + 
+		"	            ^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// passing unknown value to nonnull parameter  - target method is consumed from .class
+public void test_nonnull_parameter_005() {
+	runConformTestWithLibs(
+			new String[] {
+				"Lib.java",
+				"import org.eclipse.jdt.annotation.*;\n" +
+				"public class Lib {\n" +
+				"    void setObject(@NonNull Object o) { }\n" +
+				"}\n"
+			},
+			null /*customOptions*/,
+			"");
+	runConformTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			  "public class X {\n" +
+			  "    void bar(Lib l, Object o) {\n" +
+			  "        l.setObject(o);\n" +
+			  "    }\n" +
+			  "}\n"},
+		null /* options */,
+		"----------\n" + 
+		"1. WARNING in X.java (at line 3)\n" + 
+		"	l.setObject(o);\n" + 
+		"	            ^\n" + 
+		"Potential type mismatch: required \'@NonNull Object\' but nullness of the provided value is unknown\n" + 
+		"----------\n");
+}
+// a ternary non-null expression is passed to a nonnull parameter
+public void test_nonnull_parameter_006() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    	void m1(@NonNull String a) {}\n" + 
+			  "		void m2(@Nullable String b) {\n" + 
+			  "			m1(b == null ? \"\" : b);\n" + 
+			  "		}\n" +
+			  "}\n"},
+		customOptions,
+		""  /* compiler output */);
+}
+// nullable value passed to a non-null parameter in a super-call
+public void test_nonnull_parameter_007() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"XSub.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class XSub extends XSuper {\n" +
+			  "    	XSub(@Nullable String b) {\n" + 
+			  "			super(b);\n" + 
+			  "		}\n" +
+			  "}\n",
+			"XSuper.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class XSuper {\n" +
+			  "    	XSuper(@NonNull String b) {\n" + 
+			  "		}\n" +
+			  "}\n"
+		},		
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in XSub.java (at line 4)\n" + 
+		"	super(b);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// a nullable value is passed to a non-null parameter in an allocation expression
+public void test_nonnull_parameter_008() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    	X(@NonNull String a) {}\n" + 
+			  "		static X create(@Nullable String b) {\n" + 
+			  "			return new X(b);\n" + 
+			  "		}\n" +
+			  "}\n"},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 5)\n" + 
+		"	return new X(b);\n" + 
+		"	             ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n"  /* compiler output */);
+}
+// a nullable value is passed to a non-null parameter in a qualified allocation expression
+public void test_nonnull_parameter_009() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    class Local {\n" +
+			  "    	   Local(@NonNull String a) {}\n" +
+			  "    }\n" + 
+			  "	   Local create(@Nullable String b) {\n" + 
+			  "	       return this.new Local(b);\n" + 
+			  "    }\n" +
+			  "}\n"},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 7)\n" + 
+		"	return this.new Local(b);\n" + 
+		"	                      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n"  /* compiler output */);
+}
+// assigning potential null to a nonnull local variable
+public void test_nonnull_local_001() {
+	runNegativeTest(
+		new String[] {
+			"X.java",
+			  "import org.eclipse.jdt.annotation.*;\n" +
+			  "public class X {\n" +
+			  "    void foo(boolean b, Object p) {\n" +
+			  "        @NonNull Object o1 = b ? null : new Object();\n" +
+			  "        @NonNull String o2 = \"\";\n" +
+			  "        o2 = null;\n" +
+			  "        @NonNull Object o3 = p;\n" +
+			  "    }\n" +
+			  "}\n"},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	@NonNull Object o1 = b ? null : new Object();\n" + 
+		"	                     ^^^^^^^^^^^^^^^^^^^^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 6)\n" + 
+		"	o2 = null;\n" + 
+		"	     ^^^^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value is null\n" + 
+		"----------\n" + 
+		"3. WARNING in X.java (at line 7)\n" + 
+		"	@NonNull Object o3 = p;\n" + 
+		"	                     ^\n" + 
+		"Potential type mismatch: required \'@NonNull Object\' but nullness of the provided value is unknown\n" + 
+		"----------\n",
+		this.LIBS,
+		true /* shouldFlush*/);
+}
+
+// a method tries to tighten the type specification, super declares parameter o as @Nullable
+// other parameters: s is redefined from not constrained to @Nullable which is OK
+//                   third is redefined from not constrained to @NonNull which is bad, too
+public void test_parameter_specification_inheritance_001() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    void foo(String s, @Nullable Object o, Object third) { }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X extends Lib {\n" +
+			"    @Override\n" +
+			"    void foo(@Nullable String s, @NonNull Object o, @NonNull Object third) { System.out.print(o.toString()); }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	void foo(@Nullable String s, @NonNull Object o, @NonNull Object third) { System.out.print(o.toString()); }\n" + 
+		"	                             ^^^^^^^^^^^^^^^\n" + 
+		"Illegal redefinition of parameter o, inherited method from Lib declares this parameter as @Nullable\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 4)\n" + 
+		"	void foo(@Nullable String s, @NonNull Object o, @NonNull Object third) { System.out.print(o.toString()); }\n" + 
+		"	                                                ^^^^^^^^^^^^^^^\n" + 
+		"Illegal redefinition of parameter third, inherited method from Lib does not constrain this parameter\n" + 
+		"----------\n");
+}
+// a method body fails to redeclare the inherited null annotation, super declares parameter as @Nullable
+public void test_parameter_specification_inheritance_002() {
+	runConformTest(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    void foo(@Nullable Object o) { }\n" +
+			"}\n"
+		},
+		"",
+	    this.LIBS,
+	    false/*shouldFlush*/,
+	    null/*vmArgs*/);
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"public class X extends Lib {\n" +
+			"    @Override\n" +
+			"    void foo(Object o) {\n" +
+			"        System.out.print(o.toString());\n" +
+			"    }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 3)\n" + 
+		"	void foo(Object o) {\n" + 
+		"	         ^^^^^^\n" + 
+		"Missing null annotation: inherited method from Lib declares this parameter as @Nullable\n" + 
+		"----------\n");
+}
+// a method relaxes the parameter null specification, super interface declares parameter o as @NonNull
+// other (first) parameter just repeats the inherited @NonNull
+public void test_parameter_specification_inheritance_003() {
+	runConformTest(
+		new String[] {
+			"IX.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public interface IX {\n" +
+			"    void foo(@NonNull String s, @NonNull Object o);\n" +
+			"}\n",
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X implements IX {\n" +
+			"    public void foo(@NonNull String s, @Nullable Object o) { ; }\n" +
+			"    void bar() { foo(\"OK\", null); }\n" +
+			"}\n"
+		},
+		"",
+	    this.LIBS,
+	    false/*shouldFlush*/,
+	    null/*vmArgs*/);
+}
+// a method adds a @NonNull annotation, super interface has no null annotation
+// changing other from unconstrained to @Nullable is OK
+public void test_parameter_specification_inheritance_004() {
+	runConformTest(
+		new String[] {
+			"IX.java",
+			"public interface IX {\n" +
+			"    void foo(Object o, Object other);\n" +
+			"}\n"
+		});
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X implements IX {\n" +
+			"    public void foo(@NonNull Object o, @Nullable Object other) { System.out.print(o.toString()); }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 3)\n" + 
+		"	public void foo(@NonNull Object o, @Nullable Object other) { System.out.print(o.toString()); }\n" + 
+		"	                ^^^^^^^^^^^^^^^\n" + 
+		"Illegal redefinition of parameter o, inherited method from IX does not constrain this parameter\n" + 
+		"----------\n");
+}
+// a method tries to relax the null contract, super declares @NonNull return
+public void test_parameter_specification_inheritance_005() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    @NonNull Object getObject() { return new Object(); }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, //dont' flush
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X extends Lib {\n" +
+			"    @Override\n" +
+			"    @Nullable Object getObject() { return null; }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	@Nullable Object getObject() { return null; }\n" + 
+		"	^^^^^^^^^^^^^^^^\n" + 
+		"The return type is incompatible with the @NonNull return from Lib.getObject()\n" + 
+		"----------\n");
+}
+
+// super has no constraint for return, sub method confirms the null contract as @Nullable 
+public void test_parameter_specification_inheritance_006() {
+	runConformTest(
+		new String[] {
+			"Lib.java",
+			"public class Lib {\n" +
+			"    Object getObject() { return null; }\n" +
+			"}\n"
+		});
+	runConformTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X extends Lib {\n" +
+			"    @Override\n" +
+			"    @Nullable Object getObject() { return null; }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+}
+// a method body violates the inherited null specification, super declares @NonNull return, missing redeclaration
+public void test_parameter_specification_inheritance_007() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    @NonNull Object getObject() { return new Object(); }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"public class X extends Lib {\n" +
+			"    @Override\n" +
+			"    Object getObject() { return null; }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 3)\n" + 
+		"	Object getObject() { return null; }\n" + 
+		"	^^^^^^\n" + 
+		"The return type is incompatible with the @NonNull return from Lib.getObject()\n" + 
+		"----------\n");
+}
+//a method body violates the @NonNull return specification (repeated from super)
+public void test_parameter_specification_inheritance_007a() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    @NonNull Object getObject() { return new Object(); }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X extends Lib {\n" +
+			"    @Override\n" +
+			"    @NonNull Object getObject() { return null; }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	@NonNull Object getObject() { return null; }\n" + 
+		"	                                     ^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" + 
+		"----------\n");
+}
+// a client potentially violates the inherited null specification, super interface declares @NonNull parameter
+public void test_parameter_specification_inheritance_008() {
+	Map options = getCompilerOptions();
+	options.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+			"IX.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public interface IX {\n" +
+			"    void printObject(@NonNull Object o);\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"public class X implements IX {\n" +
+			"    public void printObject(Object o) { System.out.print(o.toString()); }\n" +
+			"}\n",
+			"M.java",
+			"public class M{\n" +
+			"    void foo(IX x, Object o) {\n" +
+			"        x.printObject(o);\n" +
+			"    }\n" +
+			"}\n"
+		},
+		options,
+		"----------\n" + 
+		// additional error:
+		"1. ERROR in X.java (at line 2)\n" + 
+		"	public void printObject(Object o) { System.out.print(o.toString()); }\n" + 
+		"	                        ^^^^^^\n" + 
+		"Missing null annotation: inherited method from IX declares this parameter as @NonNull\n" + 
+		"----------\n" +
+		// main error:
+		"----------\n" + 
+		"1. ERROR in M.java (at line 3)\n" + 
+		"	x.printObject(o);\n" + 
+		"	              ^\n" + 
+		"Potential type mismatch: required \'@NonNull Object\' but nullness of the provided value is unknown\n" + 
+		"----------\n");
+}
+// a static method has a more relaxed null contract than a like method in the super class, but no overriding.
+public void test_parameter_specification_inheritance_009() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    @NonNull static Object getObject() { return new Object(); }\n" +
+			"}\n",
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X extends Lib {\n" +
+			"    @Nullable static Object getObject() { return null; }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+}
+// class default is nonnull, method and its super both use the default
+public void test_parameter_specification_inheritance_010() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    protected String getString(String s) {\n" +
+			"        if (Character.isLowerCase(s.charAt(0)))\n" +
+			"	        return getString(s);\n" +
+			"	     return s;\n" +
+			"    }\n" +
+			"}\n",
+	"p1/Y.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class Y extends X {\n" +
+			"    @Override\n" +
+			"    protected String getString(String s) {\n" +
+			"	     return super.getString(s);\n" +
+			"    }\n" +
+			"}\n",
+		},
+		customOptions,
+		"");
+}
+// class default is nonnull, method and its super both use the default, super-call passes null
+public void test_parameter_specification_inheritance_011() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    protected String getString(String s) {\n" +
+			"        if (Character.isLowerCase(s.charAt(0)))\n" +
+			"	        return getString(s);\n" +
+			"	     return s;\n" +
+			"    }\n" +
+			"}\n",
+	"p1/Y.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class Y extends X {\n" +
+			"    @Override\n" +
+			"    protected String getString(String s) {\n" +
+			"	     return super.getString(null);\n" +
+			"    }\n" +
+			"}\n",
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p1\\Y.java (at line 7)\n" + 
+		"	return super.getString(null);\n" + 
+		"	                       ^^^^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value is null\n" + 
+		"----------\n");
+}
+// methods from two super types have different null contracts.
+// sub-class merges both using the weakest common contract 
+public void test_parameter_specification_inheritance_012() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    public @Nullable String getString(String s1, @Nullable String s2, @NonNull String s3) {\n" +
+			"	     return s1;\n" +
+			"    }\n" +
+			"}\n",
+	"p1/IY.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public interface IY {\n" +
+			"    @NonNull String getString(@NonNull String s1, @NonNull String s2, @Nullable String s3);\n" +
+			"}\n",
+	"p1/Y.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Y extends X implements IY {\n" +
+			"    @Override\n" +
+			"    public @NonNull String getString(@Nullable String s1, @Nullable String s2, @Nullable String s3) {\n" +
+			"	     return \"\";\n" +
+			"    }\n" +
+			"}\n",
+		},
+		customOptions,
+		"");
+}
+// methods from two super types have different null contracts.
+// sub-class overrides this method in non-conforming ways 
+public void test_parameter_specification_inheritance_013() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    public @Nullable String getString(String s1, @Nullable String s2, @NonNull String s3) {\n" +
+			"	     return s1;\n" +
+			"    }\n" +
+			"}\n",
+	"p1/IY.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public interface IY {\n" +
+			"    @NonNull String getString(@NonNull String s1, @NonNull String s2, @Nullable String s3);\n" +
+			"}\n",
+	"p1/Y.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Y extends X implements IY {\n" +
+			"    @Override\n" +
+			"    public @Nullable String getString(String s1, @NonNull String s2, @NonNull String s3) {\n" +
+			"	     return \"\";\n" +
+			"    }\n" +
+			"}\n",
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p1\\Y.java (at line 5)\n" + 
+		"	public @Nullable String getString(String s1, @NonNull String s2, @NonNull String s3) {\n" + 
+		"	       ^^^^^^^^^^^^^^^^\n" + 
+		"The return type is incompatible with the @NonNull return from IY.getString(String, String, String)\n" + 
+		"----------\n" + 
+		"2. ERROR in p1\\Y.java (at line 5)\n" + 
+		"	public @Nullable String getString(String s1, @NonNull String s2, @NonNull String s3) {\n" + 
+		"	                                  ^^^^^^\n" + 
+		"Missing null annotation: inherited method from IY declares this parameter as @NonNull\n" + 
+		"----------\n" + 
+		"3. ERROR in p1\\Y.java (at line 5)\n" + 
+		"	public @Nullable String getString(String s1, @NonNull String s2, @NonNull String s3) {\n" + 
+		"	                                             ^^^^^^^^^^^^^^^\n" + 
+		"Illegal redefinition of parameter s2, inherited method from X declares this parameter as @Nullable\n" + 
+		"----------\n" + 
+		"4. ERROR in p1\\Y.java (at line 5)\n" + 
+		"	public @Nullable String getString(String s1, @NonNull String s2, @NonNull String s3) {\n" + 
+		"	                                                                 ^^^^^^^^^^^^^^^\n" + 
+		"Illegal redefinition of parameter s3, inherited method from IY declares this parameter as @Nullable\n" + 
+		"----------\n");
+}
+// methods from two super types have different null contracts.
+// sub-class does not override, but should to bridge the incompatibility
+public void test_parameter_specification_inheritance_014() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/IY.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public interface IY {\n" +
+			"    public @NonNull String getString1(String s);\n" +
+			"    public @NonNull String getString2(String s);\n" +
+			"    public String getString3(@Nullable String s);\n" +
+			"    public @NonNull String getString4(@Nullable String s);\n" +
+			"    public @NonNull String getString5(@Nullable String s);\n" +
+			"    public @Nullable String getString6(@NonNull String s);\n" +
+			"}\n",
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    public @Nullable String getString1(String s) {\n" + // incomp. return
+			"	     return s;\n" +
+			"    }\n" +
+			"    public String getString2(String s) {\n" +			 // incomp. return
+			"	     return s;\n" +
+			"    }\n" +
+			"    public String getString3(String s) {\n" +			 // incomp. arg
+			"	     return \"\";\n" +
+			"    }\n" +
+			"    public @NonNull String getString4(@Nullable String s) {\n" +
+			"	     return \"\";\n" +
+			"    }\n" +
+			"    public @NonNull String getString5(@NonNull String s) {\n" + // incomp. arg
+			"	     return s;\n" +
+			"    }\n" +
+			"    public @NonNull String getString6(@Nullable String s) {\n" +
+			"	     return \"\";\n" +
+			"    }\n" +
+			"}\n",
+	"p1/Y.java",
+			"package p1;\n" +
+			"public class Y extends X implements IY {\n" +
+			"}\n",
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p1\\Y.java (at line 2)\n" + 
+		"	public class Y extends X implements IY {\n" + 
+		"	             ^\n" + 
+		"The method getString1(String) from class X cannot implement the corresponding method from type IY due to incompatible nullness constraints\n" + 
+		"----------\n" + 
+		"2. ERROR in p1\\Y.java (at line 2)\n" + 
+		"	public class Y extends X implements IY {\n" + 
+		"	             ^\n" + 
+		"The method getString2(String) from class X cannot implement the corresponding method from type IY due to incompatible nullness constraints\n" + 
+		"----------\n" + 
+		"3. ERROR in p1\\Y.java (at line 2)\n" + 
+		"	public class Y extends X implements IY {\n" + 
+		"	             ^\n" + 
+		"The method getString5(String) from class X cannot implement the corresponding method from type IY due to incompatible nullness constraints\n" + 
+		"----------\n" + 
+		"4. ERROR in p1\\Y.java (at line 2)\n" + 
+		"	public class Y extends X implements IY {\n" + 
+		"	             ^\n" + 
+		"The method getString3(String) from class X cannot implement the corresponding method from type IY due to incompatible nullness constraints\n" + 
+		"----------\n");
+}
+// a nullable return value is dereferenced without a check
+public void test_nullable_return_001() {
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @Nullable Object getObject() { return null; }\n" +
+			"    void foo() {\n" +
+			"        Object o = getObject();\n" +
+			"        System.out.print(o.toString());\n" +
+			"    }\n" +
+			"}\n"
+		},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 6)\n" + 
+		"	System.out.print(o.toString());\n" + 
+		"	                 ^\n" + 
+		"Potential null pointer access: The variable o may be null at this location\n" + 
+		"----------\n");
+}
+// a nullable return value is dereferenced without a check, method is read from .class file
+public void test_nullable_return_002() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    @Nullable Object getObject() { return null; }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"public class X {\n" +
+			"    void foo(Lib l) {\n" +
+			"        Object o = l.getObject();\n" +
+			"        System.out.print(o.toString());\n" +
+			"    }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	System.out.print(o.toString());\n" + 
+		"	                 ^\n" + 
+		"Potential null pointer access: The variable o may be null at this location\n" + 
+		"----------\n");
+}
+// a non-null return value is checked for null, method is read from .class file
+public void test_nonnull_return_001() {
+	runConformTestWithLibs(
+		new String[] {
+			"Lib.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Lib {\n" +
+			"    @NonNull Object getObject() { return new Object(); }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"");
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+			"X.java",
+			"public class X {\n" +
+			"    void foo(Lib l) {\n" +
+			"        Object o = l.getObject();\n" +
+			"        if (o != null)\n" +
+			"            System.out.print(o.toString());\n" +
+			"    }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	if (o != null)\n" + 
+		"	    ^\n" + 
+		"Redundant null check: The variable o cannot be null at this location\n" + 
+		"----------\n");
+}
+// a non-null method returns null
+public void test_nonnull_return_003() {
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject(boolean b) {\n" +
+			"        if (b)\n" +
+			"            return null;\n" + // definite specification violation despite enclosing "if"
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 5)\n" + 
+		"	return null;\n" + 
+		"	       ^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" + 
+		"----------\n");
+}
+// a non-null method potentially returns null
+public void test_nonnull_return_004() {
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject(@Nullable Object o) {\n" +
+			"        return o;\n" + // 'o' is only potentially null
+			"    }\n" +
+			"}\n"
+		},
+		null /*customOptions*/,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	return o;\n" + 
+		"	       ^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// a non-null method returns its non-null argument
+public void test_nonnull_return_005() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject(@NonNull Object o) {\n" +
+			"        return o;\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"");
+}
+//a non-null method has insufficient nullness info for its return value
+public void test_nonnull_return_006() {
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject(Object o) {\n" +
+			"        return o;\n" +
+			"    }\n" +
+			"}\n"
+		},
+		"----------\n" + 
+		"1. WARNING in X.java (at line 4)\n" + 
+		"	return o;\n" + 
+		"	       ^\n" + 
+		"Potential type mismatch: required \'@NonNull Object\' but nullness of the provided value is unknown\n" + 
+		"----------\n");
+}
+// a result from a nullable method is directly dereferenced
+public void test_nonnull_return_007() {
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @Nullable Object getObject() {\n" +
+			"        return null;\n" +
+			"    }\n" +
+			"    void test() {\n" +
+			"        getObject().toString();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 7)\n" + 
+		"	getObject().toString();\n" + 
+		"	^^^^^^^^^^^\n" + 
+		"Potential null pointer access: The method getObject() may return null\n" + 
+		"----------\n");
+}
+// a result from a nonnull method is directly checked for null: redundant
+public void test_nonnull_return_008() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportRedundantNullCheck, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject() {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"    void test() {\n" +
+			"        if (getObject() == null)\n" +
+			"		     throw new RuntimeException();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 7)\n" + 
+		"	if (getObject() == null)\n" + 
+		"	    ^^^^^^^^^^^\n" + 
+		"Redundant null check: The method getObject() cannot return null\n" + 
+		"----------\n");
+}
+// a result from a nonnull method is directly checked for null (from local): redundant
+public void test_nonnull_return_009() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportRedundantNullCheck, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject() {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"    void test() {\n" +
+			"        Object left = null;\n" +
+			"        if (left != getObject())\n" +
+			"		     throw new RuntimeException();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 8)\n" + 
+		"	if (left != getObject())\n" + 
+		"	    ^^^^\n" + 
+		"Redundant null check: The variable left can only be null at this location\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 8)\n" + 
+		"	if (left != getObject())\n" + 
+		"	            ^^^^^^^^^^^\n" + 
+		"Redundant null check: The method getObject() cannot return null\n" + 
+		"----------\n");
+}
+// a result from a nullable method is assigned and checked for null (from local): not redundant
+// see also Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
+public void test_nonnull_return_010() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportRedundantNullCheck, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @Nullable X getX() {\n" +
+			"        return new X();\n" +
+			"    }\n" +
+			"    void test() {\n" +
+			"        X left = this;\n" +
+			"        do {\n" +
+			"            if (left == null) \n" +
+			"	   	         throw new RuntimeException();\n" +
+			"        } while ((left = left.getX()) != null);\n" + // no warning/error here!
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 9)\n" + 
+		"	if (left == null) \n" + 
+		"	    ^^^^\n" + 
+		"Null comparison always yields false: The variable left cannot be null at this location\n" + 
+		"----------\n");
+}
+// a non-null method returns a checked-for null value, but that branch is dead code
+public void test_nonnull_return_011() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    Object getObject(Object dubious) {\n" +
+			"        if (dubious == null)\n" + // redundant
+			"            return dubious;\n" + // definitely null, but not reported inside dead code
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 5)\n" + 
+		"	if (dubious == null)\n" + 
+		"	    ^^^^^^^\n" + 
+		"Null comparison always yields false: The variable dubious cannot be null at this location\n" + 
+		"----------\n" + 
+		"2. WARNING in X.java (at line 6)\n" + 
+		"	return dubious;\n" + 
+		"	^^^^^^^^^^^^^^^\n" + 
+		"Dead code\n" + 
+		"----------\n");
+}
+// a non-null method returns a definite null from a conditional expression
+// requires the fix for Bug 354554 - [null] conditional with redundant condition yields weak error message
+// TODO(SH): ENABLE!
+public void _test_nonnull_return_012() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    Object getObject(Object dubious) {\n" +
+			"        return dubious == null ? dubious : null;\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 5)\n" + 
+		"	return dubious == null ? dubious : null;\n" + 
+		"	       ^^^^^^^\n" + 
+		"Null comparison always yields false: The variable dubious cannot be null at this location\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 5)\n" + 
+		"	return dubious == null ? dubious : null;\n" + 
+		"	       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" + 
+		"----------\n");
+}
+// don't apply any default annotations to return void
+public void test_nonnull_return_013() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    void getObject() {}\n" +
+			"}\n",
+			"Y.java",
+			"public class Y extends X {\n" +
+			"    @Override\n" +
+			"    void getObject() {}\n" + // don't complain, void takes no (default) annotation
+			"}\n"
+		},
+		customOptions,
+		"");
+}
+//suppress an error regarding null-spec violation
+public void test_suppress_001() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_SuppressOptionalErrors, CompilerOptions.ENABLED);
+	runConformTestWithLibs(
+			new String[] {
+				"X.java",
+				"import org.eclipse.jdt.annotation.*;\n" +
+				"public class X {\n" +
+				"    @SuppressWarnings(\"null\")\n" +
+				"    @NonNull Object getObject(@Nullable Object o) {\n" +
+				"        return o;\n" + // 'o' is only potentially null
+				"    }\n" +
+				"}\n"
+			},
+			customOptions,
+			"");	
+}
+// mixed use of fully qualified name / explicit import
+public void test_annotation_import_001() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NullableAnnotationName, "org.foo.Nullable");
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.NonNull");
+	runConformTestWithLibs(
+		new String[] {
+			CUSTOM_NULLABLE_NAME,
+			CUSTOM_NULLABLE_CONTENT,
+			CUSTOM_NONNULL_NAME,
+			CUSTOM_NONNULL_CONTENT,
+			"Lib.java",
+			"public class Lib {\n" +
+			"    @org.foo.NonNull Object getObject() { return new Object(); }\n" + 	// FQN
+			"}\n",
+			"X.java",
+			"import org.foo.NonNull;\n" +											// explicit import
+			"public class X {\n" +
+			"    @NonNull Object getObject(@NonNull Lib l) {\n" +
+			"        return l.getObject();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"");
+}
+
+// use of explicit imports throughout
+public void test_annotation_import_002() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NullableAnnotationName, "org.foo.Nullable");
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.NonNull");
+	runConformTest(
+		new String[] {
+			CUSTOM_NULLABLE_NAME,
+			CUSTOM_NULLABLE_CONTENT,
+			CUSTOM_NONNULL_NAME,
+			CUSTOM_NONNULL_CONTENT,
+			"Lib.java",
+			"import org.foo.NonNull;\n" +
+			"public class Lib {\n" +
+			"    @NonNull Object getObject() { return new Object(); }\n" +
+			"}\n",
+			"X.java",
+			"import org.foo.NonNull;\n" +
+			"public class X {\n" +
+			"    @NonNull Object getObject(@org.foo.Nullable String dummy, @NonNull Lib l) {\n" +
+			"        Object o = l.getObject();" +
+			"        return o;\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"");
+}
+// explicit import of existing annotation types
+// using a Lib without null specifications
+public void test_annotation_import_005() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NullableAnnotationName, "org.foo.MayBeNull");
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.MustNotBeNull");
+	runNegativeTest(
+		true/*shouldFlushOutputDirectory*/,
+		new String[] {
+			"org/foo/MayBeNull.java",
+			"package org.foo;\n" +
+			"import java.lang.annotation.*;\n" +
+			"@Retention(RetentionPolicy.CLASS)\n" +
+			"public @interface MayBeNull {}\n",
+			
+			"org/foo/MustNotBeNull.java",
+			"package org.foo;\n" +
+			"import java.lang.annotation.*;\n" +
+			"@Retention(RetentionPolicy.CLASS)\n" +
+			"public @interface MustNotBeNull {}\n",
+
+			"Lib.java",
+			"public class Lib {\n" +
+			"    Object getObject() { return new Object(); }\n" +
+			"}\n",
+			"X.java",
+			"import org.foo.*;\n" +
+			"public class X {\n" +
+			"    @MustNotBeNull Object getObject(@MustNotBeNull Lib l) {\n" +
+			"        return l.getObject();\n" +
+			"    }\n" +
+			"}\n",
+			
+		},
+		null /*no libs*/,
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 4)\n" + 
+		"	return l.getObject();\n" + 
+		"	       ^^^^^^^^^^^^^\n" + 
+		"Potential type mismatch: required \'@MustNotBeNull Object\' but nullness of the provided value is unknown\n" + 
+		"----------\n",
+		JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
+}
+// a non-null method returns a value obtained from an unannotated method, missing annotation types
+public void test_annotation_import_006() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NullableAnnotationName, "org.foo.MayBeNull");
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.MustNotBeNull");
+	runNegativeTest(
+		true/*shouldFlushOutputDirectory*/,
+		new String[] {
+			"Lib.java",
+			"public class Lib {\n" +
+			"    Object getObject() { return new Object(); }\n" +
+			"}\n",
+			"X.java",
+			"public class X {\n" +
+			"    @MustNotBeNull Object getObject(@MustNotBeNull Lib l) {\n" +
+			"        return l.getObject();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		null /* no libs */,
+		customOptions,
+		"----------\n" +
+		"1. ERROR in X.java (at line 2)\n" + 
+		"	@MustNotBeNull Object getObject(@MustNotBeNull Lib l) {\n" + 
+		"	 ^^^^^^^^^^^^^\n" + 
+		"MustNotBeNull cannot be resolved to a type\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 2)\n" + 
+		"	@MustNotBeNull Object getObject(@MustNotBeNull Lib l) {\n" + 
+		"	                                 ^^^^^^^^^^^^^\n" + 
+		"MustNotBeNull cannot be resolved to a type\n" + 
+		"----------\n",
+		JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
+}
+// using nullness defaulting to nonnull, missing annotation types
+public void test_annotation_import_007() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportNullSpecInsufficientInfo, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NullableAnnotationName, "org.foo.MayBeNull");
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.MustNotBeNull");
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	runNegativeTest(
+		true/*shouldFlushOutputDirectory*/,
+		new String[] {
+			"Lib.java",
+			"public class Lib {\n" +
+			"    Object getObject() { return new Object(); }\n" +
+			"}\n",
+			"X.java",
+			"public class X {\n" +
+			"    Object getObject(Lib l) {\n" +
+			"        return l.getObject();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		this.LIBS,
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in Lib.java (at line 1)\n" + 
+		"	public class Lib {\n" + 
+		"	^\n" + 
+		"Buildpath problem: the type org.foo.MustNotBeNull which is configured as a null annotation type cannot be resolved\n" + 
+		"----------\n",
+		JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
+}
+
+// a null annotation is illegally used on a class:
+public void test_illegal_annotation_001() {
+	runNegativeTest(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNull public class X {\n" +
+			"}\n"
+		},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 2)\n" + 
+		"	@NonNull public class X {\n" + 
+		"	^^^^^^^^\n" + 
+		"The annotation @NonNull is disallowed for this location\n" + 
+		"----------\n",
+		this.LIBS,
+		false/*shouldFlush*/);
+}
+// this test has been removed:
+// setting default to nullable, default applies to a parameter
+// public void test_default_nullness_001()
+
+// a null annotation is illegally defined by its simple name
+public void test_illegal_annotation_002() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "NichtNull");
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"public class X {\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 0)\n" + 
+		"	public class X {\n" + 
+		"	^\n" + 
+		"Cannot use the unqualified name \'NichtNull\' as an annotation name for null specification\n" + 
+		"----------\n");
+}
+public void test_default_nullness_002() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    Object getObject(@Nullable Object o) {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n",
+			"Y.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Y extends X {\n" +
+			"    @Override\n" +
+			"    @Nullable Object getObject(Object o) {\n" + // complain illegal return redef and inherited annot is not repeated
+			"        return o;\n" +
+			"    }\n" +
+			"}\n",
+		},
+		customOptions,
+		// main error:
+		"----------\n" + 
+		"1. ERROR in Y.java (at line 4)\n" + 
+		"	@Nullable Object getObject(Object o) {\n" + 
+		"	^^^^^^^^^^^^^^^^\n" + 
+		"The return type is incompatible with the @NonNull return from X.getObject(Object)\n" + 
+		"----------\n" +
+		// additional error:
+		"2. ERROR in Y.java (at line 4)\n" + 
+		"	@Nullable Object getObject(Object o) {\n" + 
+		"	                           ^^^^^^\n" + 
+		"Illegal redefinition of parameter o, inherited method from X declares this parameter as @Nullable\n" + 
+		"----------\n");
+}
+// package default is non-null
+public void test_default_nullness_003() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    protected Object getObject(@Nullable Object o) {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n",
+	"p2/package-info.java",
+			"@org.eclipse.jdt.annotation.NonNullByDefault\n" +
+			"package p2;\n",
+	"p2/Y.java",
+			"package p2;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Y extends p1.X {\n" +
+			"    @Override\n" +
+			"    protected @Nullable Object getObject(@Nullable Object o) {\n" +
+			"        bar(o);\n" +
+			"        return o;\n" +
+			"    }\n" +
+			"	 void bar(Object o2) { }\n" + // parameter is nonnull per package default
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p2\\Y.java (at line 5)\n" + 
+		"	protected @Nullable Object getObject(@Nullable Object o) {\n" + 
+		"	          ^^^^^^^^^^^^^^^^\n" + 
+		"The return type is incompatible with the @NonNull return from X.getObject(Object)\n" + 
+		"----------\n" + 
+		"2. ERROR in p2\\Y.java (at line 6)\n" + 
+		"	bar(o);\n" + 
+		"	    ^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// package level default is consumed from package-info.class
+public void test_default_nullness_003a() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    protected Object getObject(@Nullable Object o) {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"	 protected void bar(Object o2) { }\n" + // parameter is nonnull per type default
+			"}\n",
+	"p2/package-info.java",
+			"@org.eclipse.jdt.annotation.NonNullByDefault\n" +
+			"package p2;\n",
+			},
+			customOptions,
+			"");
+	// check if default is visible from package-info.class.
+	runNegativeTestWithLibs(
+		false, // don't flush
+		new String[] {
+	"p2/Y.java",
+			"package p2;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Y extends p1.X {\n" +
+			"    @Override\n" +
+			"    protected @Nullable Object getObject(@Nullable Object o) {\n" + // can't override inherited default nonnull 
+			"        bar(o);\n" + // parameter is nonnull in super class's .class file
+			"        accept(o);\n" +
+			"        return o;\n" +
+			"    }\n" +
+			"    void accept(Object a) {}\n" + // governed by package level default
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p2\\Y.java (at line 5)\n" + 
+		"	protected @Nullable Object getObject(@Nullable Object o) {\n" + 
+		"	          ^^^^^^^^^^^^^^^^\n" + 
+		"The return type is incompatible with the @NonNull return from X.getObject(Object)\n" + 
+		"----------\n" + 
+		"2. ERROR in p2\\Y.java (at line 6)\n" + 
+		"	bar(o);\n" + 
+		"	    ^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"3. ERROR in p2\\Y.java (at line 7)\n" + 
+		"	accept(o);\n" + 
+		"	       ^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// don't apply type-level default to non-reference type
+public void test_default_nullness_004() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    protected Object getObject(boolean o) {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n",
+	"p2/Y.java",
+			"package p2;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class Y extends p1.X {\n" +
+			"    @Override\n" +
+			"    protected @NonNull Object getObject(boolean o) {\n" +
+			"        return o ? this : new Object();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"");
+}
+// package default is non-null
+// see also Bug 354536 - compiling package-info.java still depends on the order of compilation units
+public void test_default_nullness_005() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.NonNull");
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"public class X {\n" +
+			"    class Inner {" +
+			"        protected Object getObject(String s) {\n" +
+			"            return null;\n" +
+			"        }\n" +
+			"    }\n" +
+			"}\n",
+	"p1/package-info.java",
+			"@org.eclipse.jdt.annotation.NonNullByDefault\n" +
+			"package p1;\n",
+	CUSTOM_NONNULL_NAME,
+			CUSTOM_NONNULL_CONTENT
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p1\\X.java (at line 4)\n" + 
+		"	return null;\n" + 
+		"	       ^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" + 
+		"----------\n");
+}
+// package default is non-null, package-info.java read before the annotation type
+// compile order: beginToCompile(X.Inner) triggers reading of package-info.java before the annotation type was read
+public void test_default_nullness_006() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullAnnotationName, "org.foo.NonNull");
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/package-info.java",
+			"@org.eclipse.jdt.annotation.NonNullByDefault\n" +
+			"package p1;\n",
+	"p1/X.java",
+			"package p1;\n" +
+			"public class X {\n" +
+			"    class Inner {" +
+			"        protected Object getObject(String s) {\n" +
+			"            return null;\n" +
+			"        }\n" +
+			"    }\n" +
+			"}\n",
+	CUSTOM_NONNULL_NAME,
+			CUSTOM_NONNULL_CONTENT
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in p1\\X.java (at line 4)\n" + 
+		"	return null;\n" + 
+		"	       ^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" + 
+		"----------\n");
+}
+// global default nonnull, but return may be null 
+public void test_default_nullness_007() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    @Nullable Object dangerous() {\n" +
+			"        return null;\n" + 
+			"    }\n" +
+			"    Object broken() {\n" +
+			"        return dangerous();\n" +
+			"    }\n" +
+			"}\n",
+
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 7)\n" + 
+		"	return dangerous();\n" + 
+		"	       ^^^^^^^^^^^\n" + 
+		"Type mismatch: required \'@NonNull Object\' but the provided value can be null\n" + 
+		"----------\n");
+}
+
+// cancel type level default to comply with super specification
+public void test_default_nullness_008() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"public class X {\n" +
+			"    protected Object getObject(Object o) {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n",
+	"p2/Y.java",
+			"package p2;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class Y extends p1.X {\n" +
+			"    @Override\n" +
+			"    @NonNullByDefault(false)\n" +
+			"    protected Object getObject(Object o) {\n" +
+			"        if (o.toString().length() == 0)\n" + // dereference without a warning
+			"	        return null;\n" + // return null without a warning
+			"        return o.toString();\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"");
+}
+
+// cancel outer type level default to comply with super specification
+public void test_default_nullness_009() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	runNegativeTestWithLibs(
+		new String[] {
+	"p1/X.java",
+			"package p1;\n" +
+			"public class X {\n" +
+			"    protected Object getObject(Object o) {\n" +
+			"        return new Object();\n" +
+			"    }\n" +
+			"}\n",
+	"p2/Y.java",
+			"package p2;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class Y { \n" +
+			"    @NonNullByDefault(false)\n" +
+			"    static class Z extends p1.X {\n" +
+			"        @Override\n" +
+			"        protected Object getObject(Object o) {\n" +
+			"            if (o.toString().length() == 0) {\n" +
+			"                o = null;\n" + // assign null without a warning
+			"                bar(o); // error: arg is declared @NonNull\n" +
+			"	             return null;\n" +
+			"            }\n" +
+			"            return o.toString();\n" +
+			"        }\n" +
+			"        String bar(@NonNull Object o) {\n" +
+			"            return getObject(o).toString();" +
+			"        }\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" +
+		"1. ERROR in p2\\Y.java (at line 11)\n" + 
+		"	bar(o); // error: arg is declared @NonNull\n" +
+		"	    ^\n" +
+		"Type mismatch: required \'@NonNull Object\' but the provided value is null\n" +
+		"----------\n");
+}
+// non-null declarations are redundant within a default scope.
+public void test_default_nullness_010() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	runConformTestWithLibs(
+		new String[] {
+	"p2/Y.java",
+			"package p2;\n" +
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class Y {\n" +
+			"    protected @NonNull Object getObject(@NonNull Object o) {\n" +
+			"        return o;\n" +
+			"    }\n" +
+			"}\n"
+		},
+		customOptions,
+		"----------\n" + 
+		"1. WARNING in p2\\Y.java (at line 5)\n" + 
+		"	protected @NonNull Object getObject(@NonNull Object o) {\n" + 
+		"	          ^^^^^^^^^^^^^^^\n" + 
+		"The nullness annotation is redundant with a default that applies to this location\n" + 
+		"----------\n" + 
+		"2. WARNING in p2\\Y.java (at line 5)\n" + 
+		"	protected @NonNull Object getObject(@NonNull Object o) {\n" + 
+		"	                                    ^^^^^^^^^^^^^^^^^\n" + 
+		"The nullness annotation is redundant with a default that applies to this location\n" + 
+		"----------\n");
+}
+// a nonnull variable is dereferenced in a loop
+public void test_nonnull_var_in_constrol_structure_1() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    void print4(@NonNull String s) {\n" +
+			"        for (int i=0; i<4; i++)\n" +
+			"             print(s);\n" + 
+			"    }\n" +
+			"    void print5(@Nullable String s) {\n" +
+			"        for (int i=0; i<5; i++)\n" +
+			"             print(s);\n" + 
+			"    }\n" +
+			"    void print6(boolean b) {\n" +
+			"        String s = b ? null : \"\";\n" +
+			"        for (int i=0; i<5; i++)\n" +
+			"             print(s);\n" + 
+			"    }\n" +
+			"    void print(@NonNull String s) {\n" +
+			"        System.out.print(s);\n" +
+			"    }\n" +
+			"}\n",
+
+		},
+		customOptions,
+		"----------\n" + 
+		"1. WARNING in X.java (at line 3)\n" + 
+		"	void print4(@NonNull String s) {\n" + 
+		"	            ^^^^^^^^^^^^^^^^^\n" + 
+		"The nullness annotation is redundant with a default that applies to this location\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 9)\n" + 
+		"	print(s);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"3. ERROR in X.java (at line 14)\n" + 
+		"	print(s);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"4. WARNING in X.java (at line 16)\n" + 
+		"	void print(@NonNull String s) {\n" + 
+		"	           ^^^^^^^^^^^^^^^^^\n" + 
+		"The nullness annotation is redundant with a default that applies to this location\n" + 
+		"----------\n");
+}
+// a nonnull variable is dereferenced in a finally block
+public void test_nonnull_var_in_constrol_structure_2() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    void print4(String s) {\n" +
+			"        try { /*empty*/ } finally {\n" +
+			"             print(s);\n" +
+			"        }\n" + 
+			"    }\n" +
+			"    void print5(@Nullable String s) {\n" +
+			"        try { /*empty*/ } finally {\n" +
+			"             print(s);\n" +
+			"        }\n" + 
+			"    }\n" +
+			"    void print6(boolean b) {\n" +
+			"        String s = b ? null : \"\";\n" +
+			"        try { /*empty*/ } finally {\n" +
+			"             print(s);\n" +
+			"        }\n" + 
+			"    }\n" +
+			"    void print(String s) {\n" +
+			"        System.out.print(s);\n" +
+			"    }\n" +
+			"}\n",
+
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 10)\n" + 
+		"	print(s);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 16)\n" + 
+		"	print(s);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// a nonnull variable is dereferenced in a finally block inside a loop
+public void test_nonnull_var_in_constrol_structure_3() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	customOptions.put(CompilerOptions.OPTION_ReportRedundantNullAnnotation, CompilerOptions.IGNORE);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"public class X {\n" +
+			"    void print4(@NonNull String s) {\n" +
+			"        for (int i=0; i<4; i++)\n" +
+			"            try { /*empty*/ } finally {\n" +
+			"                 print(s);\n" +
+			"            }\n" + 
+			"    }\n" +
+			"    void print5(@Nullable String s) {\n" +
+			"        for (int i=0; i<5; i++)\n" +
+			"            try { /*empty*/ } finally {\n" +
+			"                 print(s);\n" +
+			"            }\n" + 
+			"    }\n" +
+			"    void print6(boolean b) {\n" +
+			"        String s = b ? null : \"\";\n" +
+			"        for (int i=0; i<4; i++)\n" +
+			"            try { /*empty*/ } finally {\n" +
+			"                 print(s);\n" +
+			"            }\n" + 
+			"    }\n" +
+			"    void print(@NonNull String s) {\n" +
+			"        System.out.print(s);\n" +
+			"    }\n" +
+			"}\n",
+
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 12)\n" + 
+		"	print(s);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 19)\n" + 
+		"	print(s);\n" + 
+		"	      ^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// a nonnull variable is dereferenced method of a nested type
+public void test_nesting_1() {
+	Map customOptions = getCompilerOptions();
+	customOptions.put(CompilerOptions.OPTION_ReportNullReference, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_ReportPotentialNullSpecViolation, CompilerOptions.ERROR);
+	customOptions.put(CompilerOptions.OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+	runNegativeTestWithLibs(
+		new String[] {
+			"X.java",
+			"import org.eclipse.jdt.annotation.*;\n" +
+			"@NonNullByDefault\n" +
+			"public class X {\n" +
+			"    void print4(final String s1) {\n" +
+			"        for (int i=0; i<3; i++)\n" +
+			"            new Runnable() {\n" +
+			"                public void run() {\n" +
+			"                     print(s1);\n" +
+			"                }\n" +
+			"            }.run();\n" + 
+			"    }\n" +
+			"    void print8(final @Nullable String s2) {\n" +
+			"        for (int i=0; i<3; i++)\n" +
+			"            new Runnable() {\n" +
+			"                public void run() {\n" +
+			"                     print(s2);\n" +
+			"                }\n" +
+			"            }.run();\n" + 
+			"    }\n" +
+			"    void print16(boolean b) {\n" +
+			"        final String s3 = b ? null : \"\";\n" +
+			"        for (int i=0; i<3; i++)\n" +
+			"            new Runnable() {\n" +
+			"                public void run() {\n" +
+			"                     @NonNull String s3R = s3;\n" +
+			"                }\n" +
+			"            }.run();\n" + 
+			"    }\n" +
+			"    void print(String s) {\n" +
+			"        System.out.print(s);\n" +
+			"    }\n" +
+			"}\n",
+
+		},
+		customOptions,
+		"----------\n" + 
+		"1. ERROR in X.java (at line 16)\n" + 
+		"	print(s2);\n" + 
+		"	      ^^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n" + 
+		"2. ERROR in X.java (at line 25)\n" + 
+		"	@NonNull String s3R = s3;\n" + 
+		"	                      ^^\n" + 
+		"Type mismatch: required \'@NonNull String\' but the provided value can be null\n" + 
+		"----------\n");
+}
+// Test a regression incurred to the OT/J based implementation
+// by the fix in Bug 360328 - [compiler][null] detect null problems in nested code (local class inside a loop)
+public void test_constructor_with_nested_class() {
+	runConformTest(
+		new String[] {
+			"X.java",
+			"public class X {\n" +
+			"    final Object o1;\n" +
+			"    final Object o2;\n" +
+			"    public X() {\n" +
+			"         this.o1 = new Object() {\n" +
+			"             public String toString() { return \"O1\"; }\n" +
+			"         };\n" +
+			"         this.o2 = new Object();" +
+			"    }\n" +
+			"}\n"
+		},
+		"");
+}
+}
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/TestAll.java	
+++ a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/TestAll.java	
@@ -96,6 +96,7 @@ 
 	since_1_5.add(InnerEmulationTest_1_5.class);
 	since_1_5.add(AssignmentTest_1_5.class);
 	since_1_5.add(InnerClass15Test.class);
+	since_1_5.add(NullAnnotationTest.class);
 
 	// Tests to run when compliance is greater than 1.5
 	ArrayList since_1_6 = new ArrayList();
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/core/compiler/IProblem.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/core/compiler/IProblem.java	
@@ -1412,6 +1412,38 @@ 
 	/** @since 3.8 */
 	int SwitchOnEnumNotBelow15 = TypeRelated + 890;	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=360317
 	/**
+	 * Errors/warnings from annotation based null analysis
+	 */
+	/** @since 3.8 */
+	int RequiredNonNullButProvidedNull = TypeRelated + 910;
+	/** @since 3.8 */
+	int RequiredNonNullButProvidedPotentialNull = TypeRelated + 911;
+	/** @since 3.8 */
+	int RequiredNonNullButProvidedUnknown = TypeRelated + 912;
+	/** @since 3.8 */
+	int MissingNullAnnotationType = ImportRelated + 913;
+	/** @since 3.8 */
+	int NullAnnotationNameMustBeQualified = Internal + 914;
+	/** @since 3.8 */
+	int IllegalReturnNullityRedefinition = MethodRelated + 915;
+	/** @since 3.8 */
+	int IllegalRedefinitionToNonNullParameter = MethodRelated + 916;
+	/** @since 3.8 */
+	int IllegalDefinitionToNonNullParameter = MethodRelated + 917;
+	/** @since 3.8 */
+	int ParameterLackingNonNullAnnotation = MethodRelated + 918;
+	/** @since 3.8 */
+	int ParameterLackingNullableAnnotation = MethodRelated + 919;
+	/** @since 3.8 */
+	int PotentialNullMessageSendReference = Internal + 920;
+	/** @since 3.8 */
+	int RedundantNullCheckOnNonNullMessageSend = Internal + 921;
+	/** @since 3.8 */
+	int CannotImplementIncompatibleNullness = Internal + 922;
+	/** @since 3.8 */
+	int RedundantNullAnnotation = MethodRelated + 923;
+	
+	/**
 	 * External problems -- These are problems defined by other plugins
 	 */
 
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ASTNode.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ASTNode.java	
@@ -254,6 +254,14 @@ 
 	// this is only used for method invocation as the expression inside an expression statement
 	public static final int InsideExpressionStatement = Bit5;
 
+	// for annotation reference, signal if annotation was created from a default:
+	public static final int IsSynthetic = ASTNode.Bit7;
+	// for name reference within a memberValuePair of an annotation:
+	public static final int IsMemberValueReference = ASTNode.Bit15;
+
+	// for method declaration to avoid duplicate invocation of bindArguments()
+	public static final int HasBoundArguments = ASTNode.Bit10; 
+
 	public ASTNode() {
 
 		super();
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/AbstractMethodDeclaration.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/AbstractMethodDeclaration.java	
@@ -10,8 +10,11 @@ 
  *******************************************************************************/
 package org.eclipse.jdt.internal.compiler.ast;
 
+import java.util.Arrays;
+
 import org.eclipse.jdt.core.compiler.*;
 import org.eclipse.jdt.internal.compiler.*;
+import org.eclipse.jdt.internal.compiler.flow.FlowInfo;
 import org.eclipse.jdt.internal.compiler.impl.*;
 import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
 import org.eclipse.jdt.internal.compiler.codegen.*;
@@ -66,13 +69,50 @@ 
 				throw new AbortMethod(this.compilationResult, problem);
 		}
 	}
+	
+	/** 
+	 * Materialize a null annotation that has been added from the current default,
+	 * in order to ensure that this annotation will be generated into the .class file, too.
+	 */
+	public void addNullnessAnnotation(ReferenceBinding annotationBinding) {
+		this.annotations = addAnnotation(this, this.annotations, annotationBinding);
+	}
+
+	/** 
+	 * Materialize a null parameter annotation that has been added from the current default,
+	 * in order to ensure that this annotation will be generated into the .class file, too.
+	 */
+	public void addParameterNonNullAnnotation(int i, ReferenceBinding annotationBinding) {
+		Argument argument = this.arguments[i];
+		if (argument.type != null) // null happens for constructors of anonymous classes
+			argument.annotations = addAnnotation(argument.type, argument.annotations, annotationBinding);
+	}
+
+	private Annotation[] addAnnotation(ASTNode location, Annotation[] oldAnnotations, ReferenceBinding annotationBinding) {
+		long pos = ((long)location.sourceStart<<32) + location.sourceEnd;
+		long[] poss = new long[annotationBinding.compoundName.length];
+		Arrays.fill(poss, pos);
+		MarkerAnnotation annotation = new MarkerAnnotation(new QualifiedTypeReference(annotationBinding.compoundName, poss), location.sourceStart);
+		annotation.declarationSourceEnd = location.sourceEnd;
+		annotation.resolvedType = annotationBinding;
+		annotation.bits = IsSynthetic;
+		if (oldAnnotations == null) {
+			oldAnnotations = new Annotation[] {annotation};
+		} else {
+			int len = oldAnnotations.length;
+			System.arraycopy(oldAnnotations, 0, oldAnnotations=new Annotation[len+1], 1, len);
+			oldAnnotations[0] = annotation;
+		}
+		return oldAnnotations;
+	}
 
 	/**
 	 * Bind and add argument's binding into the scope of the method
 	 */
 	public void bindArguments() {
 
-		if (this.arguments != null) {
+		if (this.arguments != null && (this.bits & HasBoundArguments) == 0) {
+			this.bits |= HasBoundArguments;
 			// by default arguments in abstract/native methods are considered to be used (no complaint is expected)
 			if (this.binding == null) {
 				for (int i = 0, length = this.arguments.length; i < length; i++) {
@@ -85,6 +125,12 @@ 
 			for (int i = 0, length = this.arguments.length; i < length; i++) {
 				Argument argument = this.arguments[i];
 				argument.bind(this.scope, this.binding.parameters[i], used);
+				// argument.bind() has resolved annotations, now transfer nullness info from the argument to the method:
+				if ((argument.binding.tagBits & (TagBits.AnnotationNonNull|TagBits.AnnotationNullable)) != 0) {
+					if (this.binding.parameterNonNullness == null)
+						this.binding.parameterNonNullness = new Boolean[this.arguments.length];
+					this.binding.parameterNonNullness[i] = Boolean.valueOf((argument.binding.tagBits & TagBits.AnnotationNonNull) != 0);
+				}
 				if (argument.annotations != null) {
 					if (paramAnnotations == null) {
 						paramAnnotations = new AnnotationBinding[length][];
@@ -143,6 +189,21 @@ 
 		}
 	}
 
+	void analyseArgumentNullity(FlowInfo info) {
+		if (this.arguments != null && this.binding.parameterNonNullness != null) {
+			for (int i = 0, count = this.arguments.length; i < count; i++) {
+				// leverage null-info from parameter annotations:
+				Boolean nonNullNess = this.binding.parameterNonNullness[i];
+				if (nonNullNess != null) {
+					if (nonNullNess.booleanValue())
+						info.markAsDefinitelyNonNull(this.arguments[i].binding);
+					else
+						info.markPotentiallyNullBit(this.arguments[i].binding);
+				}
+			}
+		}
+	}
+
 	public CompilationResult compilationResult() {
 
 		return this.compilationResult;
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/AllocationExpression.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/AllocationExpression.java	
@@ -53,6 +53,7 @@ 
 				this.arguments[i].checkNPE(currentScope, flowContext, flowInfo);
 			}
 		}
+		analyseArguments(currentScope, flowContext, flowInfo, this.binding, this.arguments);
 	}
 	// record some dependency information for exception types
 	ReferenceBinding[] thrownExceptions;
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Annotation.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Annotation.java	
@@ -173,6 +173,22 @@ 
 			case TypeIds.T_JavaxAnnotationPreDestroy :
 				tagBits |= TagBits.AnnotationPreDestroy;
 				break;
+			case TypeIds.T_ConfiguredAnnotationNullable :
+				tagBits |= TagBits.AnnotationNullable;
+				break;
+			case TypeIds.T_ConfiguredAnnotationNonNull :
+				tagBits |= TagBits.AnnotationNonNull;
+				break;
+			case TypeIds.T_ConfiguredAnnotationNonNullByDefault :
+				if (valueAttribute != null 
+					&& valueAttribute.value instanceof FalseLiteral) 
+				{
+					// parameter 'false' means: this annotation cancels any defaults
+					tagBits |= TagBits.AnnotationNullUnspecifiedByDefault;
+					break;
+				}
+				tagBits |= TagBits.AnnotationNonNullByDefault;
+				break;
 		}
 		return tagBits;
 	}
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Assignment.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Assignment.java	
@@ -65,7 +65,7 @@ 
 				FlowContext.CAN_ONLY_NULL | FlowContext.IN_ASSIGNMENT, flowInfo);
 		}
 	}
-	nullStatus = checkAgainstNullAnnotation(currentScope, local, nullStatus);
+	nullStatus = checkAssignmentAgainstNullAnnotation(currentScope, flowContext, local, nullStatus, this.expression);
 	if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) {
 		flowInfo.markNullStatus(local, nullStatus);
 		if (flowContext.initsOnFinally != null)
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ConstructorDeclaration.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ConstructorDeclaration.java	
@@ -113,9 +113,19 @@ 
 			}
 		}
 
-		// tag parameters as being set
 		if (this.arguments != null) {
 			for (int i = 0, count = this.arguments.length; i < count; i++) {
+				if (this.binding.parameterNonNullness != null) {
+					// leverage null-info from parameter annotations:
+					Boolean nonNullNess = this.binding.parameterNonNullness[i];
+					if (nonNullNess != null) {
+						if (nonNullNess.booleanValue())
+							flowInfo.markAsDefinitelyNonNull(this.arguments[i].binding);
+						else
+							flowInfo.markPotentiallyNullBit(this.arguments[i].binding);
+					}
+				}
+				// tag parameters as being set
 				flowInfo.markAsDefinitelyAssigned(this.arguments[i].binding);
 			}
 		}
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/EqualExpression.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/EqualExpression.java	
@@ -1,5 +1,5 @@ 
 /*******************************************************************************
- * Copyright (c) 2000, 2010 IBM Corporation and others.
+ * Copyright (c) 2000, 2011 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -23,6 +23,21 @@ 
 		super(left,right,operator);
 	}
 	private void checkNullComparison(BlockScope scope, FlowContext flowContext, FlowInfo flowInfo, FlowInfo initsWhenTrue, FlowInfo initsWhenFalse) {
+		// check sends to null-annotated methods:
+		MessageSend leftMessage = (this.left instanceof MessageSend) ? (MessageSend) this.left : null;
+		if (   leftMessage != null 
+			&& leftMessage.nullStatus(flowInfo) == FlowInfo.NON_NULL
+			&& this.right.nullStatus(flowInfo) == FlowInfo.NULL) 
+		{
+			scope.problemReporter().messageSendRedundantCheckOnNonNull(leftMessage.binding, leftMessage);
+		}
+		MessageSend rightMessage = (this.right instanceof MessageSend) ? (MessageSend) this.right : null;
+		if (   rightMessage != null 
+			&& rightMessage.nullStatus(flowInfo) == FlowInfo.NON_NULL 
+			&& this.left.nullStatus(flowInfo) == FlowInfo.NULL) 
+		{
+			scope.problemReporter().messageSendRedundantCheckOnNonNull(rightMessage.binding, rightMessage);
+		}
 
 		LocalVariableBinding local = this.left.localVariableBinding();
 		if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) {
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ExplicitConstructorCall.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ExplicitConstructorCall.java	
@@ -81,6 +81,7 @@ 
 						this.arguments[i].checkNPE(currentScope, flowContext, flowInfo);
 					}
 				}
+				analyseArguments(currentScope, flowContext, flowInfo, this.binding, this.arguments);
 			}
 
 			ReferenceBinding[] thrownExceptions;
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/LocalDeclaration.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/LocalDeclaration.java	
@@ -85,7 +85,7 @@ 
 		this.bits &= ~FirstAssignmentToLocal;  // int i = (i = 0);
 	}
 	flowInfo.markAsDefinitelyAssigned(this.binding);
-	nullStatus = checkAgainstNullAnnotation(currentScope, this.binding, nullStatus);		
+	nullStatus = checkAssignmentAgainstNullAnnotation(currentScope, flowContext, this.binding, nullStatus, this.initialization);		
 	if ((this.binding.type.tagBits & TagBits.IsBaseType) == 0) {
 		flowInfo.markNullStatus(this.binding, nullStatus);
 		// no need to inform enclosing try block since its locals won't get
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/MemberValuePair.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/MemberValuePair.java	
@@ -1,5 +1,5 @@ 
 /*******************************************************************************
- * Copyright (c) 2000, 2010 IBM Corporation and others.
+ * Copyright (c) 2000, 2011 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -41,6 +41,9 @@ 
 		if (value instanceof ArrayInitializer) {
 			value.bits |= IsAnnotationDefaultValue;
 		}
+		if (value instanceof NameReference) {
+			value.bits |= IsMemberValueReference;
+		}
 	}
 
 	/* (non-Javadoc)
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/MessageSend.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/MessageSend.java	
@@ -99,6 +99,7 @@ 
 			flowInfo = FakedTrackingVariable.markPassedToOutside(currentScope, this.arguments[i], flowInfo);
 			flowInfo = this.arguments[i].analyseCode(currentScope, flowContext, flowInfo).unconditionalInits();
 		}
+		analyseArguments(currentScope, flowContext, flowInfo, this.binding, this.arguments);
 	}
 	ReferenceBinding[] thrownExceptions;
 	if ((thrownExceptions = this.binding.thrownExceptions) != Binding.NO_EXCEPTIONS) {
@@ -114,6 +115,11 @@ 
 	}
 	manageSyntheticAccessIfNecessary(currentScope, flowInfo);
 	return flowInfo;
+}
+public void checkNPE(BlockScope scope, FlowContext flowContext, FlowInfo flowInfo) {
+	super.checkNPE(scope, flowContext, flowInfo);
+	if (nullStatus(flowInfo) == FlowInfo.POTENTIALLY_NULL)
+		scope.problemReporter().messageSendPotentialNullReference(this.binding, this);
 }
 /**
  * @see org.eclipse.jdt.internal.compiler.ast.Expression#computeConversion(org.eclipse.jdt.internal.compiler.lookup.Scope, org.eclipse.jdt.internal.compiler.lookup.TypeBinding, org.eclipse.jdt.internal.compiler.lookup.TypeBinding)
@@ -268,9 +274,16 @@ 
 	}
 }
 public int nullStatus(FlowInfo flowInfo) {
+	if (this.binding.isValidBinding()) {
+		// try to retrieve null status of this message send from an annotation of the called method:
+		long tagBits = this.binding.tagBits;
+		if ((tagBits & TagBits.AnnotationNonNull) != 0)
+			return FlowInfo.NON_NULL;
+		if ((tagBits & TagBits.AnnotationNullable) != 0)
+			return FlowInfo.POTENTIALLY_NULL;
+	}
 	return FlowInfo.UNKNOWN;
 }
-
 /**
  * @see org.eclipse.jdt.internal.compiler.ast.Expression#postConversionType(Scope)
  */
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/MethodDeclaration.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/MethodDeclaration.java	
@@ -79,9 +79,19 @@ 
 					this.scope,
 					FlowInfo.DEAD_END);
 
-			// tag parameters as being set
 			if (this.arguments != null) {
 				for (int i = 0, count = this.arguments.length; i < count; i++) {
+					if (this.binding.parameterNonNullness != null) {
+						// leverage null-info from parameter annotations:
+						Boolean nonNullNess = this.binding.parameterNonNullness[i];
+						if (nonNullNess != null) {
+							if (nonNullNess.booleanValue())
+								flowInfo.markAsDefinitelyNonNull(this.arguments[i].binding);
+							else
+								flowInfo.markPotentiallyNullBit(this.arguments[i].binding);
+						}
+					}
+					// tag parameters as being set:
 					flowInfo.markAsDefinitelyAssigned(this.arguments[i].binding);
 					// if this method uses a type parameter declared by the declaring class,
 					// it can't be static. https://bugs.eclipse.org/bugs/show_bug.cgi?id=318682
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/QualifiedAllocationExpression.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/QualifiedAllocationExpression.java	
@@ -86,6 +86,7 @@ 
 					this.arguments[i].checkNPE(currentScope, flowContext, flowInfo);
 				}
 			}
+			analyseArguments(currentScope, flowContext, flowInfo, this.binding, this.arguments);
 		}
 
 		// analyse the anonymous nested type
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/QualifiedNameReference.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/QualifiedNameReference.java	
@@ -963,7 +963,11 @@ 
 							&& methodScope.lastVisibleFieldID >= 0
 							&& fieldBinding.id >= methodScope.lastVisibleFieldID
 							&& (!fieldBinding.isStatic() || methodScope.isStatic)) {
-						scope.problemReporter().forwardReference(this, this.indexOfFirstFieldBinding-1, fieldBinding);
+						if ((this.bits & IsMemberValueReference) != 0 && fieldBinding.id == methodScope.lastVisibleFieldID) {
+							// false alarm, location is NOT a field initializer but the value in a memberValuePair
+						} else {
+							scope.problemReporter().forwardReference(this, this.indexOfFirstFieldBinding-1, fieldBinding);
+						}
 					}
 					if (isFieldUseDeprecated(fieldBinding, scope, this.indexOfFirstFieldBinding == this.tokens.length ? this.bits : 0)) {
 						scope.problemReporter().deprecatedField(fieldBinding, this);	
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ReturnStatement.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ReturnStatement.java	
@@ -44,6 +44,8 @@ 
 		if ((this.expression.implicitConversion & TypeIds.UNBOXING) != 0) {
 			this.expression.checkNPE(currentScope, flowContext, flowInfo);
 		}
+		if (flowInfo.reachMode() == FlowInfo.REACHABLE)
+			checkAgainstNullAnnotation(currentScope, this.expression.nullStatus(flowInfo));
 		FakedTrackingVariable trackingVariable = FakedTrackingVariable.getCloseTrackingVariable(this.expression);
 		if (trackingVariable != null) {
 			if (methodScope != trackingVariable.methodScope)
@@ -119,6 +121,23 @@ 
 	currentScope.checkUnclosedCloseables(flowInfo, this, currentScope);
 	return FlowInfo.DEAD_END;
 }
+void checkAgainstNullAnnotation(BlockScope scope, int nullStatus) {
+	if (nullStatus != FlowInfo.NON_NULL) {
+		// if we can't prove non-null check against declared null-ness of the enclosing method:
+		long tagBits;
+		MethodBinding methodBinding;
+		try {
+			methodBinding = scope.methodScope().referenceMethod().binding;
+			tagBits = methodBinding.tagBits;
+		} catch (NullPointerException npe) {
+			return;
+		}
+		if ((tagBits & TagBits.AnnotationNonNull) != 0) {
+			char[][] annotationName = scope.environment().getNonNullAnnotationName();
+			scope.problemReporter().nullityMismatch(this.expression, methodBinding.returnType, nullStatus, annotationName);
+		}
+	}
+}
 
 /**
  * Retrun statement code generation
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Statement.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/Statement.java	
@@ -57,8 +57,35 @@ 
 	public static final int COMPLAINED_FAKE_REACHABLE = 1;
 	public static final int COMPLAINED_UNREACHABLE = 2;
 	
-/** Empty hook for checking null status against declaration using null annotations, once this will be supported. */
-protected int checkAgainstNullAnnotation(BlockScope currentScope, LocalVariableBinding local, int nullStatus) {
+
+/** Analysing arguments of MessageSend, ExplicitConstructorCall, AllocationExpression. */
+protected void analyseArguments(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo, MethodBinding methodBinding, Expression[] arguments) 
+{
+	// compare actual null-status against parameter annotations of the called method:
+	if (arguments != null && methodBinding.parameterNonNullness != null) {
+		for (int i = 0; i < arguments.length; i++) {
+			if (methodBinding.parameterNonNullness[i] == Boolean.TRUE) { 
+				TypeBinding expectedType = methodBinding.parameters[i];
+				Expression argument = arguments[i];
+				int nullStatus = argument.nullStatus(flowInfo); // slight loss of precision: should also use the null info from the receiver.
+				if (nullStatus != FlowInfo.NON_NULL) // if required non-null is not provided
+					flowContext.recordNullityMismatch(currentScope, argument, nullStatus, expectedType);
+			}
+		}
+	}
+}
+
+/** Check null-ness of 'local' against a possible null annotation */
+protected int checkAssignmentAgainstNullAnnotation(BlockScope currentScope, FlowContext flowContext,
+												   LocalVariableBinding local, int nullStatus, Expression expression)
+{
+	if (   local != null
+		&& (local.tagBits & TagBits.AnnotationNonNull) != 0 
+		&& nullStatus != FlowInfo.NON_NULL)
+	{
+		flowContext.recordNullityMismatch(currentScope, expression, nullStatus, local.type);
+		nullStatus=FlowInfo.NON_NULL;
+	}
 	return nullStatus;
 }
 
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/FinallyFlowContext.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/FinallyFlowContext.java	
@@ -17,6 +17,7 @@ 
 import org.eclipse.jdt.internal.compiler.lookup.FieldBinding;
 import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
 import org.eclipse.jdt.internal.compiler.lookup.Scope;
+import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
 import org.eclipse.jdt.internal.compiler.lookup.TypeIds;
 import org.eclipse.jdt.internal.compiler.lookup.VariableBinding;
 
@@ -83,8 +84,13 @@ 
 	// check inconsistent null checks
 	if ((this.tagBits & FlowContext.DEFER_NULL_DIAGNOSTIC) != 0) { // within an enclosing loop, be conservative
 		for (int i = 0; i < this.nullCount; i++) {
-			this.parent.recordUsingNullReference(scope, this.nullLocals[i],
-					this.nullReferences[i],	this.nullCheckTypes[i], flowInfo);
+			if (this.nullCheckTypes[i] == ASSIGN_TO_NONNULL)
+				this.parent.recordNullityMismatch(scope, this.nullReferences[i], 
+						flowInfo.nullStatus(this.nullLocals[i]), this.expectedTypes[i]);
+			else
+				this.parent.recordUsingNullReference(scope, this.nullLocals[i],
+						this.nullReferences[i],	this.nullCheckTypes[i], flowInfo);
+			
 		}
 	}
 	else { // no enclosing loop, be as precise as possible right now
@@ -165,6 +171,13 @@ 
 					}
 					if (flowInfo.isPotentiallyNull(local)) {
 						scope.problemReporter().localVariablePotentialNullReference(local, expression);
+					}
+					break;
+				case ASSIGN_TO_NONNULL:
+					int nullStatus = flowInfo.nullStatus(local);
+					if (nullStatus != FlowInfo.NON_NULL) {
+						char[][] annotationName = scope.environment().getNonNullAnnotationName();
+						scope.problemReporter().nullityMismatch(expression, this.expectedTypes[i], nullStatus, annotationName);
 					}
 					break;
 				default:
@@ -442,4 +455,14 @@ 
 	this.nullReferences[this.nullCount] = expression;
 	this.nullCheckTypes[this.nullCount++] = status;
 }
+protected boolean internalRecordNullityMismatch(Expression expression, int nullStatus, TypeBinding expectedType, int checkType) {
+	// cf. decision structure inside FinallyFlowContext.recordUsingNullReference(..)
+	if (nullStatus == FlowInfo.UNKNOWN ||
+			((this.tagBits & FlowContext.DEFER_NULL_DIAGNOSTIC) != 0 && nullStatus != FlowInfo.NULL)) {
+		recordExpectedType(expectedType, this.nullCount);
+		recordNullReference(expression.localVariableBinding(), expression, checkType);
+		return true;
+	}
+	return false;
+}
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/FlowContext.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/FlowContext.java	
@@ -52,6 +52,10 @@ 
 		// any null related operation happening within the try block
 
 	public int tagBits;
+	
+	// array to store the expected type from the potential error location (for display in error messages):
+	public TypeBinding[] expectedTypes = null;
+	
 	public static final int DEFER_NULL_DIAGNOSTIC = 0x1;
 	public static final int PREEMPT_NULL_DIAGNOSTIC = 0x2;
 	/**
@@ -66,6 +70,8 @@ 
 public static final int CAN_ONLY_NON_NULL = 0x0002;
 //check against non null, with definite values -- comparisons
 public static final int MAY_NULL = 0x0003;
+//check binding a value to a @NonNull variable 
+public final static int ASSIGN_TO_NONNULL = 0x0080;
 // check against null, with potential values -- NPE guard
 public static final int CHECK_MASK = 0x00FF;
 public static final int IN_COMPARISON_NULL = 0x0100;
@@ -548,6 +554,21 @@ 
 	// default implementation: do nothing
 }
 
+protected void recordExpectedType(TypeBinding expectedType, int nullCount) {
+	if (nullCount == 0) {
+		this.expectedTypes = new TypeBinding[5];
+	} else if (this.expectedTypes == null) {
+		int size = 5;
+		while (size <= nullCount) size *= 2;
+		this.expectedTypes = new TypeBinding[size];
+	}
+	else if (nullCount == this.expectedTypes.length) {
+		System.arraycopy(this.expectedTypes, 0,
+			this.expectedTypes = new TypeBinding[nullCount * 2], 0, nullCount);
+	}
+	this.expectedTypes[nullCount] = expectedType;
+}
+
 protected boolean recordFinalAssignment(VariableBinding variable, Reference finalReference) {
 	return true; // keep going
 }
@@ -746,4 +767,31 @@ 
 	buffer.append(individualToString()).append('\n');
 	return buffer.toString();
 }
+
+/**
+ * Record that a nullity mismatch was detected against an annotated type reference.
+ * @param currentScope scope for error reporting
+ * @param expression the expression violating the specification
+ * @param nullStatus the null status of expression at the current location
+ * @param expectedType the declared type of the spec'ed variable, for error reporting.
+ */
+public void recordNullityMismatch(BlockScope currentScope, Expression expression, int nullStatus, TypeBinding expectedType) {
+	if (expression.localVariableBinding() != null) { // flowContext cannot yet handle non-localvar expressions (e.g., fields)
+		// find the inner-most flowContext that might need deferred handling:
+		FlowContext currentContext = this;
+		while (currentContext != null) {
+			// some flow contexts implement deferred checking, should we participate in that?
+			if (currentContext.internalRecordNullityMismatch(expression, nullStatus, expectedType, ASSIGN_TO_NONNULL))										
+				return;
+			currentContext = currentContext.parent;
+		}
+	}			
+	// no reason to defer, so report now:
+	char[][] annotationName = currentScope.environment().getNonNullAnnotationName();
+	currentScope.problemReporter().nullityMismatch(expression, expectedType, nullStatus, annotationName);
+}
+protected boolean internalRecordNullityMismatch(Expression expression, int nullStatus, TypeBinding expectedType, int checkType) {
+	// nop, to be overridden in subclasses
+	return false; // not recorded
+}
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java	
@@ -12,6 +12,7 @@ 
 package org.eclipse.jdt.internal.compiler.flow;
 
 import java.util.ArrayList;
+
 import org.eclipse.jdt.internal.compiler.ast.ASTNode;
 import org.eclipse.jdt.internal.compiler.ast.Expression;
 import org.eclipse.jdt.internal.compiler.ast.Reference;
@@ -21,6 +22,7 @@ 
 import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
 import org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;
 import org.eclipse.jdt.internal.compiler.lookup.Scope;
+import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
 import org.eclipse.jdt.internal.compiler.lookup.TypeIds;
 import org.eclipse.jdt.internal.compiler.lookup.VariableBinding;
 
@@ -246,6 +248,9 @@ 
 						continue;
 					}
 					break;
+				case ASSIGN_TO_NONNULL:
+					this.parent.recordNullityMismatch(scope, expression, flowInfo.nullStatus(local), this.expectedTypes[i]);
+					break;
 				default:
 					// never happens
 			}
@@ -337,6 +342,13 @@ 
 						this.nullReferences[i] = null;
 						scope.problemReporter().localVariablePotentialNullReference(local, expression);
 						continue;
+					}
+					break;
+				case ASSIGN_TO_NONNULL:
+					int nullStatus = flowInfo.nullStatus(local);
+					if (nullStatus != FlowInfo.NON_NULL) {
+						char[][] annotationName = scope.environment().getNonNullAnnotationName();
+						scope.problemReporter().nullityMismatch(expression, this.expectedTypes[i], nullStatus, annotationName);
 					}
 					break;
 				default:
@@ -667,4 +679,10 @@ 
 	public boolean hasEscapingExceptions() {
 		return this.escapingExceptionCatchSites != null;
 	}
+
+	protected boolean internalRecordNullityMismatch(Expression expression, int nullStatus, TypeBinding expectedType, int checkType) {
+		recordExpectedType(expectedType, this.nullCount);
+		recordNullReference(expression.localVariableBinding(), expression, checkType);
+		return true;
+	}
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/impl/CompilerOptions.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/impl/CompilerOptions.java	
@@ -26,6 +26,7 @@ 
 import org.eclipse.jdt.internal.compiler.ast.ASTNode;
 import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
 import org.eclipse.jdt.internal.compiler.lookup.ExtraCompilerModifiers;
+import org.eclipse.jdt.internal.compiler.lookup.TagBits;
 import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities;
 import org.eclipse.jdt.internal.compiler.util.Util;
 
@@ -142,6 +143,19 @@ 
 	public static final String OPTION_ReportUnclosedCloseable = "org.eclipse.jdt.core.compiler.problem.unclosedCloseable"; //$NON-NLS-1$
 	public static final String OPTION_ReportPotentiallyUnclosedCloseable = "org.eclipse.jdt.core.compiler.problem.potentiallyUnclosedCloseable"; //$NON-NLS-1$
 	public static final String OPTION_ReportExplicitlyClosedAutoCloseable = "org.eclipse.jdt.core.compiler.problem.explicitlyClosedAutoCloseable"; //$NON-NLS-1$
+	public static final String OPTION_ReportNullSpecViolation = "org.eclipse.jdt.core.compiler.problem.nullSpecViolation";  //$NON-NLS-1$
+	public static final String OPTION_ReportPotentialNullSpecViolation = "org.eclipse.jdt.core.compiler.problem.potentialNullSpecViolation";  //$NON-NLS-1$
+	public static final String OPTION_ReportNullSpecInsufficientInfo = "org.eclipse.jdt.core.compiler.problem.nullSpecInsufficientInfo";  //$NON-NLS-1$
+	public static final String OPTION_ReportRedundantNullAnnotation = "org.eclipse.jdt.core.compiler.problem.redundantNullAnnotation";  //$NON-NLS-1$
+	public static final String OPTION_AnnotationBasedNullAnalysis = "org.eclipse.jdt.core.compiler.annotation.nullanalysis"; //$NON-NLS-1$
+	public static final String OPTION_NullableAnnotationName = "org.eclipse.jdt.core.compiler.annotation.nullable"; //$NON-NLS-1$
+	public static final String OPTION_NonNullAnnotationName = "org.eclipse.jdt.core.compiler.annotation.nonnull"; //$NON-NLS-1$
+	public static final String OPTION_NonNullByDefaultAnnotationName = "org.eclipse.jdt.core.compiler.annotation.nonnullbydefault"; //$NON-NLS-1$
+	// defaults for the above:
+	static final char[][] DEFAULT_NULLABLE_ANNOTATION_NAME = CharOperation.splitOn('.', "org.eclipse.jdt.annotation.Nullable".toCharArray()); //$NON-NLS-1$
+	static final char[][] DEFAULT_NONNULL_ANNOTATION_NAME = CharOperation.splitOn('.', "org.eclipse.jdt.annotation.NonNull".toCharArray()); //$NON-NLS-1$
+	static final char[][] DEFAULT_NONNULLBYDEFAULT_ANNOTATION_NAME = CharOperation.splitOn('.', "org.eclipse.jdt.annotation.NonNullByDefault".toCharArray()); //$NON-NLS-1$
+	public static final String OPTION_NonNullIsDefault = "org.eclipse.jdt.core.compiler.annotation.nonnullisdefault";  //$NON-NLS-1$
 	/**
 	 * Possible values for configurable options
 	 */
@@ -245,10 +259,13 @@ 
 	public static final int MethodCanBeStatic = IrritantSet.GROUP2 | ASTNode.Bit5;
 	public static final int MethodCanBePotentiallyStatic = IrritantSet.GROUP2 | ASTNode.Bit6;
 	public static final int RedundantSpecificationOfTypeArguments = IrritantSet.GROUP2 | ASTNode.Bit7;
-	// bits 8-10 reserved for https://bugs.eclipse.org/bugs/show_bug.cgi?id=186342
-	public static final int UnclosedCloseable = IrritantSet.GROUP2 | ASTNode.Bit11;
-	public static final int PotentiallyUnclosedCloseable = IrritantSet.GROUP2 | ASTNode.Bit12;
-	public static final int ExplicitlyClosedAutoCloseable = IrritantSet.GROUP2 | ASTNode.Bit13;
+	public static final int UnclosedCloseable = IrritantSet.GROUP2 | ASTNode.Bit8;
+	public static final int PotentiallyUnclosedCloseable = IrritantSet.GROUP2 | ASTNode.Bit9;
+	public static final int ExplicitlyClosedAutoCloseable = IrritantSet.GROUP2 | ASTNode.Bit10;
+	public static final int NullSpecViolation = IrritantSet.GROUP2 | ASTNode.Bit11;
+	public static final int PotentialNullSpecViolation = IrritantSet.GROUP2 | ASTNode.Bit12;
+	public static final int NullSpecInsufficientInfo = IrritantSet.GROUP2 | ASTNode.Bit13;
+	public static final int RedundantNullAnnotation = IrritantSet.GROUP2 | ASTNode.Bit14;
 
 	// Severity level for handlers
 	/** 
@@ -370,6 +387,18 @@ 
 	public boolean includeNullInfoFromAsserts;
 	/** Controls whether forced generic type problems get reported  */
 	public boolean reportUnavoidableGenericTypeProblems;
+
+	// === Support for Null Annotations: ===
+	/** Master switch for null analysis based on annotations: */
+	public boolean isAnnotationBasedNullAnalysisEnabled;
+	/** Fully qualified name of annotation to use as marker for nullable types. */
+	public char[][] nullableAnnotationName;
+	/** Fully qualified name of annotation to use as marker for nonnull types. */
+	public char[][] nonNullAnnotationName;
+	/** Fully qualified name of annotation to use as marker for default nonnull. */
+	public char[][] nonNullByDefaultAnnotationName;
+	/** TagBits-encoded default for non-annotated types. */
+	public long defaultNonNullness; // 0 or TagBits#AnnotationNonNull
 
 	// keep in sync with warningTokenToIrritant and warningTokenFromIrritant
 	public final static String[] warningTokens = {
@@ -567,6 +596,14 @@ 
 				return OPTION_ReportPotentiallyUnclosedCloseable;
 			case ExplicitlyClosedAutoCloseable :
 				return OPTION_ReportExplicitlyClosedAutoCloseable;
+			case NullSpecViolation :
+				return OPTION_ReportNullSpecViolation;
+			case PotentialNullSpecViolation :
+				return OPTION_ReportPotentialNullSpecViolation;
+			case NullSpecInsufficientInfo :
+				return OPTION_ReportNullSpecInsufficientInfo;
+			case RedundantNullAnnotation :
+				return OPTION_ReportRedundantNullAnnotation;
 		}
 		return null;
 	}
@@ -795,6 +832,10 @@ 
 			case NullReference :
 			case PotentialNullReference :
 			case RedundantNullCheck :
+			case NullSpecViolation :
+			case PotentialNullSpecViolation :
+			case NullSpecInsufficientInfo :
+			case RedundantNullAnnotation :
 				return "null"; //$NON-NLS-1$
 			case FallthroughCase :
 				return "fallthrough"; //$NON-NLS-1$
@@ -1008,6 +1049,29 @@ 
 		optionsMap.put(OPTION_ReportUnclosedCloseable, getSeverityString(UnclosedCloseable));
 		optionsMap.put(OPTION_ReportPotentiallyUnclosedCloseable, getSeverityString(PotentiallyUnclosedCloseable));
 		optionsMap.put(OPTION_ReportExplicitlyClosedAutoCloseable, getSeverityString(ExplicitlyClosedAutoCloseable));
+		optionsMap.put(OPTION_AnnotationBasedNullAnalysis, this.isAnnotationBasedNullAnalysisEnabled ? ENABLED : DISABLED);
+		if (this.isAnnotationBasedNullAnalysisEnabled) {
+			optionsMap.put(OPTION_ReportNullSpecViolation, getSeverityString(NullSpecViolation));
+			optionsMap.put(OPTION_ReportPotentialNullSpecViolation, getSeverityString(PotentialNullSpecViolation));
+			optionsMap.put(OPTION_ReportNullSpecInsufficientInfo, getSeverityString(NullSpecInsufficientInfo));
+			optionsMap.put(OPTION_ReportRedundantNullAnnotation, getSeverityString(RedundantNullAnnotation));
+			if (this.nullableAnnotationName != null) {
+				char[] compoundName = CharOperation.concatWith(this.nullableAnnotationName, '.');
+				optionsMap.put(OPTION_NullableAnnotationName, String.valueOf(compoundName));
+			}
+			if (this.nonNullAnnotationName != null) {
+				char[] compoundName = CharOperation.concatWith(this.nonNullAnnotationName, '.');
+				optionsMap.put(OPTION_NonNullAnnotationName, String.valueOf(compoundName));
+			}
+			if (this.nonNullByDefaultAnnotationName != null) {
+				char[] compoundName = CharOperation.concatWith(this.nonNullByDefaultAnnotationName, '.');
+				optionsMap.put(OPTION_NonNullByDefaultAnnotationName, String.valueOf(compoundName));
+			}
+			if (this.defaultNonNullness == TagBits.AnnotationNonNull)
+				optionsMap.put(OPTION_NonNullIsDefault, CompilerOptions.ENABLED);
+			else
+				optionsMap.put(OPTION_NonNullIsDefault, CompilerOptions.DISABLED);
+		}
 		return optionsMap;
 	}
 
@@ -1441,6 +1505,38 @@ 
 		if ((optionValue = optionsMap.get(OPTION_ReportUnclosedCloseable)) != null) updateSeverity(UnclosedCloseable, optionValue);
 		if ((optionValue = optionsMap.get(OPTION_ReportPotentiallyUnclosedCloseable)) != null) updateSeverity(PotentiallyUnclosedCloseable, optionValue);
 		if ((optionValue = optionsMap.get(OPTION_ReportExplicitlyClosedAutoCloseable)) != null) updateSeverity(ExplicitlyClosedAutoCloseable, optionValue);
+		if ((optionValue = optionsMap.get(OPTION_AnnotationBasedNullAnalysis)) != null) {
+			if (ENABLED.equals(optionValue)) {
+				this.isAnnotationBasedNullAnalysisEnabled = true;
+				// ensure that we actually have annotation names to use:
+				ensureNullAnnotationNames();
+			} else if (DISABLED.equals(optionValue)) {
+				this.isAnnotationBasedNullAnalysisEnabled = false;
+			}
+		}
+		if (this.isAnnotationBasedNullAnalysisEnabled) {
+			if ((optionValue = optionsMap.get(OPTION_ReportNullSpecViolation)) != null) updateSeverity(NullSpecViolation, optionValue);
+			if ((optionValue = optionsMap.get(OPTION_ReportPotentialNullSpecViolation)) != null) updateSeverity(PotentialNullSpecViolation, optionValue);
+			if ((optionValue = optionsMap.get(OPTION_ReportNullSpecInsufficientInfo)) != null) updateSeverity(NullSpecInsufficientInfo, optionValue);
+			if ((optionValue = optionsMap.get(OPTION_ReportRedundantNullAnnotation)) != null) updateSeverity(RedundantNullAnnotation, optionValue);
+			if ((optionValue = optionsMap.get(OPTION_NullableAnnotationName)) != null) {
+				this.nullableAnnotationName = CharOperation.splitAndTrimOn('.', ((String)optionValue).toCharArray());
+			}
+			if ((optionValue = optionsMap.get(OPTION_NonNullAnnotationName)) != null) {
+				this.nonNullAnnotationName = CharOperation.splitAndTrimOn('.', ((String)optionValue).toCharArray());
+			}
+			if ((optionValue = optionsMap.get(OPTION_NonNullByDefaultAnnotationName)) != null) {
+				this.nonNullByDefaultAnnotationName = CharOperation.splitAndTrimOn('.', ((String)optionValue).toCharArray());
+			}
+			if ((optionValue = optionsMap.get(OPTION_NonNullIsDefault)) != null) {
+				if (CompilerOptions.ENABLED.equals(optionValue)) {
+					this.defaultNonNullness = TagBits.AnnotationNonNull;
+					ensureNullAnnotationNames();
+				} else {
+					this.defaultNonNullness = 0;
+				}
+			}
+		}
 
 		// Javadoc options
 		if ((optionValue = optionsMap.get(OPTION_DocCommentSupport)) != null) {
@@ -1554,6 +1650,14 @@ 
 			}
 		}
 	}
+	private void ensureNullAnnotationNames() {
+		if (this.nullableAnnotationName == null)
+			this.nullableAnnotationName = CompilerOptions.DEFAULT_NULLABLE_ANNOTATION_NAME;
+		if (this.nonNullAnnotationName == null)
+			this.nonNullAnnotationName = CompilerOptions.DEFAULT_NONNULL_ANNOTATION_NAME;
+		if (this.nonNullByDefaultAnnotationName == null)
+			this.nonNullByDefaultAnnotationName = CompilerOptions.DEFAULT_NONNULLBYDEFAULT_ANNOTATION_NAME;
+	}
 	public String toString() {
 		StringBuffer buf = new StringBuffer("CompilerOptions:"); //$NON-NLS-1$
 		buf.append("\n\t- local variables debug attributes: ").append((this.produceDebugAttributes & ClassFileConstants.ATTR_VARS) != 0 ? "ON" : " OFF"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/impl/IrritantSet.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/impl/IrritantSet.java	
@@ -102,8 +102,14 @@ 
 			.set(
 				CompilerOptions.DeadCode
 				|CompilerOptions.Tasks
-				|CompilerOptions.UnclosedCloseable);
-			
+				|CompilerOptions.UnclosedCloseable
+				|CompilerOptions.NullSpecInsufficientInfo
+				|CompilerOptions.RedundantNullAnnotation);
+		// default errors IF AnnotationBasedNullAnalysis is enabled:
+		COMPILER_DEFAULT_ERRORS.set(
+				CompilerOptions.NullSpecViolation
+				|CompilerOptions.PotentialNullSpecViolation);
+
 		ALL.setAll();
 		HIDING
 			.set(CompilerOptions.FieldHiding)
@@ -111,7 +117,12 @@ 
 			.set(CompilerOptions.TypeHiding);
 		NULL
 			.set(CompilerOptions.PotentialNullReference)
-			.set(CompilerOptions.RedundantNullCheck);
+			.set(CompilerOptions.RedundantNullCheck)
+			.set(CompilerOptions.NullSpecViolation)
+			.set(CompilerOptions.PotentialNullSpecViolation)
+			.set(CompilerOptions.NullSpecInsufficientInfo)
+			.set(CompilerOptions.RedundantNullAnnotation);
+
 		RESTRICTION.set(CompilerOptions.DiscouragedReference);
 		STATIC_ACCESS.set(CompilerOptions.NonStaticAccessToStatic);
 		UNUSED
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/BinaryTypeBinding.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/BinaryTypeBinding.java	
@@ -16,6 +16,7 @@ 
 import org.eclipse.jdt.core.compiler.CharOperation;
 import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
 import org.eclipse.jdt.internal.compiler.env.*;
+import org.eclipse.jdt.internal.compiler.impl.BooleanConstant;
 import org.eclipse.jdt.internal.compiler.impl.Constant;
 import org.eclipse.jdt.internal.compiler.problem.AbortCompilation;
 import org.eclipse.jdt.internal.compiler.util.SimpleLookupTable;
@@ -383,6 +384,8 @@ 
 		}
 		if (this.environment.globalOptions.storeAnnotations)
 			setAnnotations(createAnnotations(binaryType.getAnnotations(), this.environment, missingTypeNames));
+		
+		scanTypeForNullAnnotation(binaryType);
 	} finally {
 		// protect against incorrect use of the needFieldsAndMethods flag, see 48459
 		if (this.fields == null)
@@ -589,6 +592,9 @@ 
 	// fixup the declaring element of the type variable
 	for (int i = 0, length = typeVars.length; i < length; i++)
 		typeVars[i].declaringElement = result;
+	
+	scanMethodForNullAnnotation(method, result);
+	
 	return result;
 }
 
@@ -1142,6 +1148,96 @@ 
 	}
 	return this.storedAnnotations;
 }
+void scanMethodForNullAnnotation(IBinaryMethod method, MethodBinding methodBinding) {
+	char[][] nullableAnnotationName = this.environment.getNullableAnnotationName();
+	char[][] nonNullAnnotationName = this.environment.getNonNullAnnotationName();
+	if (nullableAnnotationName == null || nonNullAnnotationName == null)
+		return; // not configured to use null annotations
+
+	// return:
+	IBinaryAnnotation[] annotations = method.getAnnotations();
+	if (annotations != null) {
+		for (int i = 0; i < annotations.length; i++) {
+			char[] annotationTypeName = annotations[i].getTypeName();
+			if (annotationTypeName[0] != 'L')
+				continue;
+			char[][] typeName = CharOperation.splitOn('/', annotationTypeName, 1, annotationTypeName.length-1); // cut of leading 'L' and trailing ';'
+			if (CharOperation.equals(typeName, nonNullAnnotationName)) {
+				methodBinding.tagBits |= TagBits.AnnotationNonNull;
+				break;
+			}
+			if (CharOperation.equals(typeName, nullableAnnotationName)) {
+				methodBinding.tagBits |= TagBits.AnnotationNullable;
+				break;
+			}
+		}
+	}
+
+	// parameters:
+	TypeBinding[] parameters = methodBinding.parameters;
+	for (int j = 0; j < parameters.length; j++) {
+		IBinaryAnnotation[] paramAnnotations = method.getParameterAnnotations(j); 
+		if (paramAnnotations != null) {
+			for (int i = 0; i < paramAnnotations.length; i++) {
+				char[] annotationTypeName = paramAnnotations[i].getTypeName();
+				if (annotationTypeName[0] != 'L')
+					continue;
+				char[][] typeName = CharOperation.splitOn('/', annotationTypeName, 1, annotationTypeName.length-1); // cut of leading 'L' and trailing ';'
+				if (CharOperation.equals(typeName, nonNullAnnotationName)) {
+					if (methodBinding.parameterNonNullness == null)
+						methodBinding.parameterNonNullness = new Boolean[parameters.length];
+					methodBinding.parameterNonNullness[j] = Boolean.TRUE;
+					break;
+				} else if (CharOperation.equals(typeName, nullableAnnotationName)) {
+					if (methodBinding.parameterNonNullness == null)
+						methodBinding.parameterNonNullness = new Boolean[parameters.length];
+					methodBinding.parameterNonNullness[j] = Boolean.FALSE;
+					break;
+				}
+			}
+		}
+	}
+}
+void scanTypeForNullAnnotation(IBinaryType binaryType) {
+	char[][] nonNullByDefaultAnnotationName = this.environment.getNonNullByDefaultAnnotationName();
+	if (nonNullByDefaultAnnotationName == null)
+		return; // not configured to use null annotations
+
+	IBinaryAnnotation[] annotations = binaryType.getAnnotations();
+	if (annotations != null) {
+		long annotationBit = 0L;
+		TypeBinding defaultNullness = null;
+		for (int i = 0; i < annotations.length; i++) {
+			char[] annotationTypeName = annotations[i].getTypeName();
+			if (annotationTypeName[0] != 'L')
+				continue;
+			char[][] typeName = CharOperation.splitOn('/', annotationTypeName, 1, annotationTypeName.length-1); // cut of leading 'L' and trailing ';'
+			if (CharOperation.equals(typeName, nonNullByDefaultAnnotationName)) {
+				IBinaryElementValuePair[] elementValuePairs = annotations[i].getElementValuePairs();
+				if (elementValuePairs != null && elementValuePairs.length == 1) {
+					Object value = elementValuePairs[0].getValue();
+					if (value instanceof BooleanConstant
+						&& !((BooleanConstant)value).booleanValue()) 
+					{
+						// parameter is 'false': this means we cancel defaults from outer scopes:
+						annotationBit = TagBits.AnnotationNullUnspecifiedByDefault;
+						defaultNullness = ReferenceBinding.NULL_UNSPECIFIED;
+						break;
+					}
+				}
+				annotationBit = TagBits.AnnotationNonNullByDefault;
+				defaultNullness = this.environment.getNullAnnotationBinding(TagBits.AnnotationNonNull, false/*resolve*/);
+				break;
+			}
+		}
+		if (annotationBit != 0L) {
+			this.tagBits |= annotationBit;
+			if (CharOperation.equals(this.sourceName(), TypeConstants.PACKAGE_INFO_NAME))
+				this.getPackage().nullnessDefaultAnnotation = defaultNullness;
+		}
+	}
+}
+
 /* Answer the receiver's superclass... null if the receiver is Object or an interface.
 *
 * NOTE: superclass of a binary type is resolved when needed
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/LookupEnvironment.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/LookupEnvironment.java	
@@ -76,6 +76,8 @@ 
 	public boolean isProcessingAnnotations = false;
 	public boolean mayTolerateMissingType = false;
 
+	boolean nullAnnotationsInitialized = false;
+
 	final static int BUILD_FIELDS_AND_METHODS = 4;
 	final static int BUILD_TYPE_HIERARCHY = 1;
 	final static int CHECK_AND_SET_IMPORTS = 2;
@@ -83,6 +85,7 @@ 
 
 	static final ProblemPackageBinding TheNotFoundPackage = new ProblemPackageBinding(CharOperation.NO_CHAR, NotFound);
 	static final ProblemReferenceBinding TheNotFoundType = new ProblemReferenceBinding(CharOperation.NO_CHAR_CHAR, null, NotFound);
+
 
 public LookupEnvironment(ITypeRequestor typeRequestor, CompilerOptions globalOptions, ProblemReporter problemReporter, INameEnvironment nameEnvironment) {
 	this.typeRequestor = typeRequestor;
@@ -723,6 +726,8 @@ 
 * 3. Create the method bindings
 */
 public PackageBinding createPackage(char[][] compoundName) {
+	if (!this.nullAnnotationsInitialized)
+		initNullAnnotationPackages();
 	PackageBinding packageBinding = getPackage0(compoundName[0]);
 	if (packageBinding == null || packageBinding == TheNotFoundPackage) {
 		packageBinding = new PackageBinding(compoundName[0], this);
@@ -1073,6 +1078,54 @@ 
 	return packageBinding.getType0(compoundName[compoundName.length - 1]);
 }
 
+public char[][] getNullableAnnotationName() {
+	return this.globalOptions.nullableAnnotationName;
+}
+
+public char[][] getNonNullAnnotationName() {
+	return this.globalOptions.nonNullAnnotationName;
+}
+
+public char[][] getNonNullByDefaultAnnotationName() {
+	return this.globalOptions.nonNullByDefaultAnnotationName;
+}
+
+/**
+ * Answer the type binding representing the null-annotation identified by the given tag bits.
+ * @param annotationTagBit tag bits potentially denoting a null-annotation
+ * @param resolve should the resulting type binding be resolved?
+ * @return the corresponding annotation type binding 
+ * 		or <code>null</code> if no annotation bits are contained in the given tag bits.
+ */
+public TypeBinding getNullAnnotationBinding(long annotationTagBit, boolean resolve) {
+	char[][] name = null;
+	if (annotationTagBit == TagBits.AnnotationNonNull)
+		name = getNonNullAnnotationName();
+	else if (annotationTagBit == TagBits.AnnotationNullable)
+		name = getNullableAnnotationName();
+	else
+		return null;
+	if (resolve)
+		return getType(name);
+	else
+		return getTypeFromCompoundName(name, false, false);
+}
+
+/**
+ * Inspect the given tag bits and answer a corresponding null annotation type binding
+ * @param defaultTagBit tag bits representing the default applicable at the current code location
+ * @param resolve should the resulting type binding be resolved?
+ * @return the corresponding concrete annotation type binding (<code>@NonNull</code> or <code>@Nullable</code>) 
+ * 		or <code>null</code> if no bits of a default-annotation are contained in the given tag bits.
+ */
+public TypeBinding getNullAnnotationBindingFromDefault(long defaultTagBit, boolean resolve) {
+	if ((defaultTagBit & TagBits.AnnotationNullUnspecifiedByDefault) != 0)
+		return ReferenceBinding.NULL_UNSPECIFIED;
+	if ((defaultTagBit & TagBits.AnnotationNonNullByDefault) != 0)
+		return getNullAnnotationBinding(TagBits.AnnotationNonNull, resolve);
+	return null;
+}
+
 /* Answer the top level package named name if it exists in the cache.
 * Answer theNotFoundPackage if it could not be resolved the first time
 * it was looked up, otherwise answer null.
@@ -1106,6 +1159,8 @@ 
 * Answer null if the package cannot be found.
 */
 PackageBinding getTopLevelPackage(char[] name) {
+	if (!this.nullAnnotationsInitialized)
+		initNullAnnotationPackages();
 	PackageBinding packageBinding = getPackage0(name);
 	if (packageBinding != null) {
 		if (packageBinding == TheNotFoundPackage)
@@ -1387,6 +1442,39 @@ 
 	}
 }
 
+private void initNullAnnotationPackages() {
+	this.nullAnnotationsInitialized = true;
+	char[][] compoundName = getNullableAnnotationName();
+	if (compoundName != null)
+		initNullAnnotationPackage(compoundName, TypeIds.T_ConfiguredAnnotationNullable);
+	compoundName = getNonNullAnnotationName();
+	if (compoundName != null)
+		initNullAnnotationPackage(compoundName, TypeIds.T_ConfiguredAnnotationNonNull);
+	compoundName = getNonNullByDefaultAnnotationName();
+	if (compoundName != null)
+		initNullAnnotationPackage(compoundName, TypeIds.T_ConfiguredAnnotationNonNullByDefault);
+}
+
+/** 
+ * Create or retrieve the package holding the specified type and store the type name.
+ */
+void initNullAnnotationPackage(char[][] typeName, int typeId) {
+	if (typeName.length < 2) {
+		this.problemReporter.nullAnnotationNameMustBeQualified(typeName);
+		return;
+	}
+	char[][] packageName = CharOperation.subarray(typeName, 0, typeName.length-1);
+	PackageBinding packageBinding = createPackage(packageName);
+	char[] simpleTypeName = typeName[typeName.length-1];
+	if (typeId == TypeIds.T_ConfiguredAnnotationNullable)
+		packageBinding.nullableName = simpleTypeName;
+	else if (typeId == TypeIds.T_ConfiguredAnnotationNonNull)
+		packageBinding.nonNullName = simpleTypeName;
+	else if (typeId == TypeIds.T_ConfiguredAnnotationNonNullByDefault)
+		packageBinding.nonNullByDefaultName = simpleTypeName;
+}
+
+
 boolean isMissingType(char[] typeName) {
 	for (int i = this.missingTypes == null ? 0 : this.missingTypes.size(); --i >= 0;) {
 		MissingTypeBinding missingType = (MissingTypeBinding) this.missingTypes.get(i);
@@ -1454,6 +1542,9 @@ 
 	this.unitBeingCompleted = null; // in case AbortException occurred
 
 	this.classFilePool.reset();
+	
+	this.nullAnnotationsInitialized = false;
+
 	// name environment has a longer life cycle, and must be reset in
 	// the code which created it.
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/MethodBinding.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/MethodBinding.java	
@@ -34,6 +34,9 @@ 
 	char[] signature;
 	public long tagBits;
 
+	/** Store nullness information from annotation (incl. applicable default). */
+	public Boolean[] parameterNonNullness;  // TRUE means @NonNull declared, FALSE means @Nullable declared, null means nothing declared
+
 protected MethodBinding() {
 	// for creating problem or synthetic method
 }
@@ -439,6 +442,41 @@ 
 	return this.selector;
 }
 
+/** 
+ * After method verifier has finished, fill in missing nullness values from the applicable default.
+ * @param annotationBinding the null annotation specified to be the default at the current code location.
+ */
+protected void fillInDefaultNonNullness(TypeBinding annotationBinding) {
+	if (this.parameterNonNullness == null)
+		this.parameterNonNullness = new Boolean[this.parameters.length];
+	AbstractMethodDeclaration sourceMethod = sourceMethod();
+	for (int i = 0; i < this.parameterNonNullness.length; i++) {
+		if (this.parameters[i].isBaseType())
+			continue;
+		boolean added = false;
+		if (this.parameterNonNullness[i] == null) {
+			added = true;
+			this.parameterNonNullness[i] = Boolean.TRUE;
+			if (sourceMethod != null)
+				sourceMethod.addParameterNonNullAnnotation(i, (ReferenceBinding)annotationBinding);
+		} else if (this.parameterNonNullness[i].booleanValue()) {
+			sourceMethod.scope.problemReporter().nullAnnotationIsRedundant(sourceMethod, i);
+		}
+		if (added)
+			this.tagBits |= TagBits.HasParameterAnnotations;
+	}
+	if (   this.returnType != null
+		&& !this.returnType.isBaseType()
+		&& (this.tagBits & (TagBits.AnnotationNonNull|TagBits.AnnotationNullable)) == 0)
+	{
+		this.tagBits |= TagBits.AnnotationNonNull;
+		if (sourceMethod != null)
+			sourceMethod.addNullnessAnnotation((ReferenceBinding)annotationBinding);
+	} else if ((this.tagBits & TagBits.AnnotationNonNull) != 0) {
+		sourceMethod.scope.problemReporter().nullAnnotationIsRedundant(sourceMethod, -1/*signifies method return*/);
+	}
+}
+
 public MethodBinding findOriginalInheritedMethod(MethodBinding inheritedMethod) {
 	MethodBinding inheritedOriginal = inheritedMethod.original();
 	TypeBinding superType = this.declaringClass.findSuperTypeOriginatingFrom(inheritedOriginal.declaringClass);
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/MethodVerifier15.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/MethodVerifier15.java	
@@ -164,6 +164,8 @@ 
 				|| this.type.superclass.erasure().findSuperTypeOriginatingFrom(originalInherited.declaringClass) == null)
 					this.type.addSyntheticBridgeMethod(originalInherited, concreteMethod.original());
 		}
+		if (!concreteMethod.isStatic() && !abstractMethod.isStatic())
+			checkNullSpecInheritance(concreteMethod, abstractMethod);
 	}
 }
 void checkForBridgeMethod(MethodBinding currentMethod, MethodBinding inheritedMethod, MethodBinding[] allInheritedMethods) {
@@ -358,6 +360,100 @@ 
 	}
 
 	return false;
+}
+void checkAgainstInheritedMethods(MethodBinding currentMethod, MethodBinding[] methods, int length, MethodBinding[] allInheritedMethods) 
+{
+	super.checkAgainstInheritedMethods(currentMethod, methods, length, allInheritedMethods);
+	for (int i = length; --i >= 0;)
+		if (!currentMethod.isStatic() && !methods[i].isStatic())
+			checkNullSpecInheritance(currentMethod, methods[i]);
+}
+
+void checkNullSpecInheritance(MethodBinding currentMethod, MethodBinding inheritedMethod) {
+	long inheritedBits = inheritedMethod.tagBits;
+	long currentBits = currentMethod.tagBits;
+	AbstractMethodDeclaration srcMethod = null;
+	if (this.type.equals(currentMethod.declaringClass)) // is currentMethod from the current type?
+		srcMethod = currentMethod.sourceMethod();
+
+	// return type:
+	if ((inheritedBits & TagBits.AnnotationNonNull) != 0) {
+		long currentNullBits = currentBits & (TagBits.AnnotationNonNull|TagBits.AnnotationNullable);
+		if (currentNullBits != TagBits.AnnotationNonNull) {
+			if (srcMethod != null) {
+				this.type.scope.problemReporter().illegalReturnRedefinition(srcMethod, inheritedMethod,
+															this.environment.getNonNullAnnotationName());
+			} else {
+				this.type.scope.problemReporter().cannotImplementIncompatibleNullness(currentMethod, inheritedMethod);
+				return;
+			}
+		}
+	}
+
+	// parameters:
+	Argument[] currentArguments = srcMethod == null ? null : srcMethod.arguments;
+	if (inheritedMethod.parameterNonNullness != null) {
+		// inherited method has null-annotations, check compatibility:
+
+		for (int i = 0; i < inheritedMethod.parameterNonNullness.length; i++) {
+			Argument currentArgument = currentArguments == null ? null : currentArguments[i];
+			
+			Boolean inheritedNonNullNess = inheritedMethod.parameterNonNullness[i];
+			Boolean currentNonNullNess = (currentMethod.parameterNonNullness == null)
+										? null : currentMethod.parameterNonNullness[i];
+			if (inheritedNonNullNess != null) {				// super has a null annotation
+				if (currentNonNullNess == null) {			// current parameter lacks null annotation
+					boolean needNonNull = false;
+					char[][] annotationName;
+					if (inheritedNonNullNess == Boolean.TRUE) {
+						needNonNull = true;
+						annotationName = this.environment.getNonNullAnnotationName();
+					} else {
+						annotationName = this.environment.getNullableAnnotationName();
+					}
+					if (currentArgument != null) {
+						this.type.scope.problemReporter().parameterLackingNonNullAnnotation(
+								currentArgument,
+								inheritedMethod.declaringClass,
+								needNonNull,
+								annotationName);
+						continue;
+					} else {
+						this.type.scope.problemReporter().cannotImplementIncompatibleNullness(currentMethod, inheritedMethod);
+						break;
+					}
+				}						
+			}
+			if (inheritedNonNullNess != Boolean.TRUE) {		// super parameter is not restricted to @NonNull
+				if (currentNonNullNess == Boolean.TRUE) { 	// current parameter is restricted to @NonNull
+					if (currentArgument != null)
+						this.type.scope.problemReporter().illegalRedefinitionToNonNullParameter(
+														currentArgument,
+														inheritedMethod.declaringClass,
+														inheritedNonNullNess == null
+														? null
+														: this.environment.getNullableAnnotationName());
+					else
+						this.type.scope.problemReporter().cannotImplementIncompatibleNullness(currentMethod, inheritedMethod);
+				} 
+			}
+		}
+	} else if (currentMethod.parameterNonNullness != null) {
+		// super method has no annotations but current has
+		for (int i = 0; i < currentMethod.parameterNonNullness.length; i++) {
+			if (currentMethod.parameterNonNullness[i] == Boolean.TRUE) { // tightening from unconstrained to @NonNull
+				if (currentArguments != null) {
+					this.type.scope.problemReporter().illegalRedefinitionToNonNullParameter(
+																	currentArguments[i],
+																	inheritedMethod.declaringClass,
+																	null);
+				} else {
+					this.type.scope.problemReporter().cannotImplementIncompatibleNullness(currentMethod, inheritedMethod);
+					break;
+				}
+			}
+		}
+	}
 }
 
 void reportRawReferences() {
@@ -932,7 +1028,7 @@ 
 boolean isUnsafeReturnTypeOverride(MethodBinding currentMethod, MethodBinding inheritedMethod) {
 	// called when currentMethod's return type is NOT compatible with inheritedMethod's return type
 
-	// JLS 3 �8.4.5: more are accepted, with an unchecked conversion
+	// JLS 3 �8.4.5: more are accepted, with an unchecked conversion
 	if (currentMethod.returnType == inheritedMethod.returnType.erasure()) {
 		TypeBinding[] currentParams = currentMethod.parameters;
 		TypeBinding[] inheritedParams = inheritedMethod.parameters;
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/PackageBinding.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/PackageBinding.java	
@@ -1,5 +1,5 @@ 
 /*******************************************************************************
- * Copyright (c) 2000, 2009 IBM Corporation and others.
+ * Copyright (c) 2000, 2011 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -22,6 +22,12 @@ 
 	public LookupEnvironment environment;
 	HashtableOfType knownTypes;
 	HashtableOfPackage knownPackages;
+
+	protected char[] nullableName = null;
+	protected char[] nonNullName = null;
+	protected char[] nonNullByDefaultName = null;
+	protected TypeBinding nullnessDefaultAnnotation;
+
 protected PackageBinding() {
 	// for creating problem package
 }
@@ -58,6 +64,8 @@ 
 	if (this.knownTypes == null)
 		this.knownTypes = new HashtableOfType(25);
 	this.knownTypes.put(element.compoundName[element.compoundName.length - 1], element);
+	if (this.nullableName != null || this.nonNullName != null || this.nonNullByDefaultName != null)
+		setupNullAnnotationType(element);
 }
 
 void clearMissingTagBit() {
@@ -230,6 +238,26 @@ 
 	return ProblemReasons.NoError;
 }
 
+void setupNullAnnotationType(ReferenceBinding type) {
+	int id = 0;
+	if (CharOperation.equals(this.nullableName, type.sourceName))
+		id = TypeIds.T_ConfiguredAnnotationNullable;
+	else if (CharOperation.equals(this.nonNullName, type.sourceName))
+		id = TypeIds.T_ConfiguredAnnotationNonNull;
+	else if (CharOperation.equals(this.nonNullByDefaultName, type.sourceName))
+		id = TypeIds.T_ConfiguredAnnotationNonNullByDefault;
+	else 
+		return;
+	
+	type.id = id;	// ensure annotations of this type are detected as standard annotations.
+}
+
+public TypeBinding getNullnessDefaultAnnotation() {
+	if (this.nullnessDefaultAnnotation instanceof UnresolvedReferenceBinding)
+		return this.nullnessDefaultAnnotation = BinaryTypeBinding.resolveType(this.nullnessDefaultAnnotation, this.environment, false);
+	return this.nullnessDefaultAnnotation;
+}
+
 public char[] readableName() /*java.lang*/ {
 	return CharOperation.concatWith(this.compoundName, '.');
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ReferenceBinding.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ReferenceBinding.java	
@@ -48,6 +48,14 @@ 
 		public boolean hasTypeBit(int bit) { return false; }
 	};
 
+	/**
+	 * This faked annotation type binding marks types with unspecified nullness.
+	 * For use in {@link PackageBinding#nullnessDefaultAnnotation} and {@link SourceTypeBinding#nullnessDefaultAnnotation} 
+	 */
+	final static ReferenceBinding NULL_UNSPECIFIED = new ReferenceBinding() { /* faked type binding */
+		public boolean hasTypeBit(int bit) { return false; }
+	};
+
 	private static final Comparator FIELD_COMPARATOR = new Comparator() {
 		public int compare(Object o1, Object o2) {
 			char[] n1 = ((FieldBinding) o1).name;
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/SourceTypeBinding.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/SourceTypeBinding.java	
@@ -54,6 +54,9 @@ 
 	char[] genericReferenceTypeSignature;
 
 	private SimpleLookupTable storedAnnotations = null; // keys are this ReferenceBinding & its fields and methods, value is an AnnotationHolder
+	
+	private TypeBinding nullnessDefaultAnnotation;
+	private int nullnessDefaultInitialized = 0; // 0: nothing; 1: type; 2: package
 
 public SourceTypeBinding(char[][] compoundName, PackageBinding fPackage, ClassScope scope) {
 	this.compoundName = compoundName;
@@ -781,6 +784,7 @@ 
 		}
 		if ((this.tagBits & TagBits.AnnotationDeprecated) != 0)
 			this.modifiers |= ClassFileConstants.AccDeprecated;
+		evaluateNullAnnotations(this.tagBits);
 	}
 	return this.tagBits;
 }
@@ -1088,6 +1092,8 @@ 
 			this.modifiers |= ClassFileConstants.AccDeprecated;
 		}
 	}
+	if (CharOperation.equals(this.sourceName, TypeConstants.PACKAGE_INFO_NAME))
+		getAnnotationTagBits(); // initialize
 }
 
 // ensure the receiver knows its hierarchy & fields/methods so static imports can be resolved correctly
@@ -1590,12 +1596,103 @@ 
 				typeParameters[i].binding = null;
 		return null;
 	}
+	callBindArguments(method);
 	if (foundReturnTypeProblem)
 		return method; // but its still unresolved with a null return type & is still connected to its method declaration
 
 	method.modifiers &= ~ExtraCompilerModifiers.AccUnresolved;
 	return method;
 }
+private void callBindArguments(MethodBinding method) {
+	switch (this.nullnessDefaultInitialized) {
+	case 0:
+		getAnnotationTagBits(); // initialize
+		//$FALL-THROUGH$
+	case 1:
+		getPackage().isViewedAsDeprecated(); // initialize annotations
+		this.nullnessDefaultInitialized = 2;
+	}
+	AbstractMethodDeclaration methodDecl = method.sourceMethod();
+	if (methodDecl != null) {
+		if (method.parameters != Binding.NO_PARAMETERS)
+			methodDecl.bindArguments();
+		TypeBinding annotationBinding = findDefaultNullness(method, methodDecl.scope.environment());
+		if (annotationBinding != null && annotationBinding.id == TypeIds.T_ConfiguredAnnotationNonNull)
+			method.fillInDefaultNonNullness(annotationBinding);
+	}
+}
+private void evaluateNullAnnotations(long annotationTagBits) {
+	if (this.nullnessDefaultInitialized > 0)
+		return;
+	this.nullnessDefaultInitialized = 1;
+	// transfer nullness info from tagBits to this.nullnessDefaultAnnotation 
+	TypeBinding defaultAnnotation = getPackage().environment
+						.getNullAnnotationBindingFromDefault(annotationTagBits, false/*resolve*/);
+	if (defaultAnnotation != null) {
+		if (CharOperation.equals(this.sourceName, TypeConstants.PACKAGE_INFO_NAME)) {
+			getPackage().nullnessDefaultAnnotation = defaultAnnotation;
+		} else {
+			this.nullnessDefaultAnnotation = defaultAnnotation;
+		}
+	}
+}
+private TypeBinding getNullnessDefaultAnnotation() {
+	if (this.nullnessDefaultAnnotation instanceof UnresolvedReferenceBinding)
+		return this.nullnessDefaultAnnotation =
+				BinaryTypeBinding.resolveType(this.nullnessDefaultAnnotation, getPackage().environment, false);
+	return this.nullnessDefaultAnnotation;
+}
+/**
+ * Answer the nullness default applicable at the given method binding.
+ * Possible values:<ul>
+ * <li>the type binding for @NonNulByDefault</li>
+ * <li>the synthetic type {@link ReferenceBinding#NULL_UNSPECIFIED} if a default from outer scope has been canceled</li>
+ * <li>null if no default has been defined</li>
+ * </ul>
+ */
+private TypeBinding findDefaultNullness(MethodBinding methodBinding, LookupEnvironment environment) {
+	// find the applicable default inside->out:
+	
+	// method
+	TypeBinding annotationBinding = environment.getNullAnnotationBindingFromDefault(methodBinding.tagBits, true/*resolve*/);
+	if (annotationBinding != null)
+		return annotationBinding;
+	
+	// type
+	ReferenceBinding type = methodBinding.declaringClass;
+	ReferenceBinding currentType = type;
+	while (currentType instanceof SourceTypeBinding) {
+		annotationBinding = ((SourceTypeBinding) currentType).getNullnessDefaultAnnotation();
+		if (annotationBinding != null)
+			return annotationBinding;
+		currentType = currentType.enclosingType();
+	}
+	
+	// package
+	annotationBinding = type.getPackage().getNullnessDefaultAnnotation();
+	if (annotationBinding != null)
+		return annotationBinding;
+	
+	// global
+	long defaultNullness = environment.globalOptions.defaultNonNullness;
+	if (defaultNullness != 0) {
+		annotationBinding = environment.getNullAnnotationBinding(defaultNullness, true/*resolve*/);
+		if (annotationBinding != null)
+			return annotationBinding;
+		
+		// on this branch default was not defined using an annotation, thus annotation type can still be missing
+		if (defaultNullness == TagBits.AnnotationNonNull)
+			this.scope.problemReporter().missingNullAnnotationType(environment.getNonNullAnnotationName());
+		else if (defaultNullness == TagBits.AnnotationNullable)
+			this.scope.problemReporter().missingNullAnnotationType(environment.getNullableAnnotationName());
+		else
+			this.scope.problemReporter().abortDueToInternalError("Illegal default nullness value: "+defaultNullness); //$NON-NLS-1$
+		// reset default to avoid duplicate errors:
+		environment.globalOptions.defaultNonNullness = 0;
+	}
+	return null;
+}
+
 public AnnotationHolder retrieveAnnotationHolder(Binding binding, boolean forceInitialization) {
 	if (forceInitialization)
 		binding.getAnnotationTagBits(); // ensure annotations are up to date
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TagBits.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TagBits.java	
@@ -132,6 +132,14 @@ 
 	long AnnotationPreDestroy = ASTNode.Bit54L;
 	/** @since 3.8 */
 	long AnnotationPostConstruct = ASTNode.Bit55L;
+	/** @since 3.8 null annotation for MethodBinding or LocalVariableBinding (argument): */
+	long AnnotationNullable = ASTNode.Bit56L;
+	/** @since 3.8 null annotation for MethodBinding or LocalVariableBinding (argument): */
+	long AnnotationNonNull = ASTNode.Bit57L;
+	/** @since 3.8 null-default annotation for PackageBinding or TypeBinding or MethodBinding: */
+	long AnnotationNonNullByDefault = ASTNode.Bit58L;
+	/** @since 3.8 canceling null-default annotation for PackageBinding or TypeBinding or MethodBinding: */
+	long AnnotationNullUnspecifiedByDefault = ASTNode.Bit59L;
 
 	long AllStandardAnnotationsMask =
 				  AnnotationTargetMASK
@@ -144,10 +152,14 @@ 
 				| AnnotationSafeVarargs
 				| AnnotationPolymorphicSignature
 				| AnnotationPostConstruct
-				| AnnotationPreDestroy;
+				| AnnotationPreDestroy
+				| AnnotationNullable
+				| AnnotationNonNull
+				| AnnotationNonNullByDefault
+				| AnnotationNullUnspecifiedByDefault;
 
-	long DefaultValueResolved = ASTNode.Bit56L;
+	long DefaultValueResolved = ASTNode.Bit60L;
 
 	// set when type contains non-private constructor(s)
-	long HasNonPrivateConstructor = ASTNode.Bit57L;
+	long HasNonPrivateConstructor = ASTNode.Bit61L;
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TypeIds.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TypeIds.java	
@@ -104,6 +104,11 @@ 
 	final int T_JavaxAnnotationPostConstruct = 63;
 
 	final int T_JavaxAnnotationPreDestroy = 64;
+	
+	// new in 3.8 for null annotations:
+	final int T_ConfiguredAnnotationNullable = 65;
+	final int T_ConfiguredAnnotationNonNull = 66;
+	final int T_ConfiguredAnnotationNonNullByDefault = 67;
 
 	final int NoId = Integer.MAX_VALUE;
 
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java	
@@ -84,6 +84,7 @@ 
 import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
 import org.eclipse.jdt.internal.compiler.env.AccessRestriction;
 import org.eclipse.jdt.internal.compiler.env.ICompilationUnit;
+import org.eclipse.jdt.internal.compiler.flow.FlowInfo;
 import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
 import org.eclipse.jdt.internal.compiler.impl.ReferenceContext;
 import org.eclipse.jdt.internal.compiler.lookup.ArrayBinding;
@@ -287,6 +288,7 @@ 
 			return CompilerOptions.NullReference;
 
 		case IProblem.PotentialNullLocalVariableReference:
+		case IProblem.PotentialNullMessageSendReference:
 			return CompilerOptions.PotentialNullReference;
 
 		case IProblem.RedundantLocalVariableNullAssignment:
@@ -295,7 +297,24 @@ 
 		case IProblem.NonNullLocalVariableComparisonYieldsFalse:
 		case IProblem.NullLocalVariableComparisonYieldsFalse:
 		case IProblem.NullLocalVariableInstanceofYieldsFalse:
+		case IProblem.RedundantNullCheckOnNonNullMessageSend:
 			return CompilerOptions.RedundantNullCheck;
+
+		case IProblem.RequiredNonNullButProvidedNull:
+		case IProblem.IllegalReturnNullityRedefinition:
+		case IProblem.IllegalRedefinitionToNonNullParameter:
+		case IProblem.IllegalDefinitionToNonNullParameter:
+		case IProblem.ParameterLackingNonNullAnnotation:
+		case IProblem.ParameterLackingNullableAnnotation:
+		case IProblem.CannotImplementIncompatibleNullness:
+			return CompilerOptions.NullSpecViolation;
+		
+		case IProblem.RequiredNonNullButProvidedPotentialNull:
+			return CompilerOptions.PotentialNullSpecViolation;
+		case IProblem.RequiredNonNullButProvidedUnknown:
+			return CompilerOptions.NullSpecInsufficientInfo;
+		case IProblem.RedundantNullAnnotation:
+			return CompilerOptions.RedundantNullAnnotation;
 
 		case IProblem.BoxingConversion :
 		case IProblem.UnboxingConversion :
@@ -542,6 +561,13 @@ 
 			case CompilerOptions.DiscouragedReference :
 				return CategorizedProblem.CAT_RESTRICTION;
 			
+			case CompilerOptions.NullSpecViolation :
+			case CompilerOptions.PotentialNullSpecViolation :
+			case CompilerOptions.NullSpecInsufficientInfo :
+				return CategorizedProblem.CAT_POTENTIAL_PROGRAMMING_PROBLEM;
+			case CompilerOptions.RedundantNullAnnotation :
+				return CategorizedProblem.CAT_UNNECESSARY_CODE;
+
 			default:
 				break categorizeOnIrritant;
 		}
@@ -550,6 +576,8 @@ 
 	switch (problemID) {
 		case IProblem.IsClassPathCorrect :
 		case IProblem.CorruptedSignature :
+		case IProblem.MissingNullAnnotationType :
+		case IProblem.NullAnnotationNameMustBeQualified :
 			return CategorizedProblem.CAT_BUILDPATH;
 
 		default :
@@ -7999,4 +8027,172 @@ 
 		trackVar.sourceStart,
 		trackVar.sourceEnd);	
 }
+
+public void nullityMismatch(Expression expression, TypeBinding requiredType, int nullStatus, char[][] annotationName) {
+	int problemId = IProblem.RequiredNonNullButProvidedUnknown;
+	if ((nullStatus & FlowInfo.NULL) != 0)
+		problemId = IProblem.RequiredNonNullButProvidedNull;
+	if ((nullStatus & FlowInfo.POTENTIALLY_NULL) != 0)
+		problemId = IProblem.RequiredNonNullButProvidedPotentialNull;
+	String[] arguments = new String[] { 
+			String.valueOf(CharOperation.concatWith(annotationName, '.')),
+			String.valueOf(requiredType.readableName())
+	};
+	String[] argumentsShort = new String[] { 
+			String.valueOf(annotationName[annotationName.length-1]),
+			String.valueOf(requiredType.shortReadableName())
+	};
+	this.handle(
+		problemId,
+		arguments,
+		argumentsShort,
+		expression.sourceStart,
+		expression.sourceEnd);
+}
+public void illegalRedefinitionToNonNullParameter(Argument argument, ReferenceBinding declaringClass, char[][] inheritedAnnotationName) {
+	int sourceStart = argument.type.sourceStart;
+	if (argument.annotations != null) {
+		for (int i=0; i<argument.annotations.length; i++) {
+			Annotation annotation = argument.annotations[i];
+			if (   annotation.resolvedType.id == TypeIds.T_ConfiguredAnnotationNullable
+				|| annotation.resolvedType.id == TypeIds.T_ConfiguredAnnotationNonNull) 
+			{
+				sourceStart = annotation.sourceStart;
+				break;
+			}
+		}
+	}
+	if (inheritedAnnotationName == null) {
+		this.handle(
+			IProblem.IllegalDefinitionToNonNullParameter, 
+			new String[] { new String(argument.name), new String(declaringClass.readableName()) },
+			new String[] { new String(argument.name), new String(declaringClass.shortReadableName()) },
+			sourceStart,
+			argument.type.sourceEnd);
+		
+	} else {
+		this.handle(
+			IProblem.IllegalRedefinitionToNonNullParameter, 
+			new String[] { new String(argument.name), new String(declaringClass.readableName()), CharOperation.toString(inheritedAnnotationName)},
+			new String[] { new String(argument.name), new String(declaringClass.shortReadableName()), new String(inheritedAnnotationName[inheritedAnnotationName.length-1])},
+			sourceStart,
+			argument.type.sourceEnd);
+	}
+}
+public void parameterLackingNonNullAnnotation(Argument argument, ReferenceBinding declaringClass, boolean needNonNull, char[][] inheritedAnnotationName) {
+	this.handle(
+		needNonNull ? IProblem.ParameterLackingNonNullAnnotation : IProblem.ParameterLackingNullableAnnotation, 
+		new String[] { new String(argument.name), new String(declaringClass.readableName()), CharOperation.toString(inheritedAnnotationName)},
+		new String[] { new String(argument.name), new String(declaringClass.shortReadableName()), new String(inheritedAnnotationName[inheritedAnnotationName.length-1])},
+		argument.type.sourceStart,
+		argument.type.sourceEnd);
+}
+public void illegalReturnRedefinition(AbstractMethodDeclaration abstractMethodDecl,
+									  MethodBinding inheritedMethod, char[][] nonNullAnnotationName) 
+{
+	MethodDeclaration methodDecl = (MethodDeclaration) abstractMethodDecl;
+	StringBuffer methodSignature = new StringBuffer();
+	methodSignature
+		.append(inheritedMethod.declaringClass.readableName())
+		.append('.')
+		.append(inheritedMethod.readableName());
+
+	StringBuffer shortSignature = new StringBuffer();
+	shortSignature
+		.append(inheritedMethod.declaringClass.shortReadableName())
+		.append('.')
+		.append(inheritedMethod.shortReadableName());
+	int sourceStart = methodDecl.returnType.sourceStart;
+	Annotation[] annotations = methodDecl.annotations;
+	if (annotations != null) {
+		for (int i=0; i<annotations.length; i++) {
+			if (annotations[i].resolvedType.id == TypeIds.T_ConfiguredAnnotationNullable) {
+				sourceStart = annotations[i].sourceStart;
+				break;
+			}
+		}
+	}
+	this.handle(
+		IProblem.IllegalReturnNullityRedefinition, 
+		new String[] { methodSignature.toString(), CharOperation.toString(nonNullAnnotationName)},
+		new String[] { shortSignature.toString(), new String(nonNullAnnotationName[nonNullAnnotationName.length-1])},
+		sourceStart, 
+		methodDecl.returnType.sourceEnd);
+}
+public void messageSendPotentialNullReference(MethodBinding method, ASTNode location) {
+	String[] arguments = new String[] {new String(method.readableName())};
+	this.handle(
+		IProblem.PotentialNullMessageSendReference,
+		arguments,
+		arguments,
+		location.sourceStart,
+		location.sourceEnd);
+}
+public void messageSendRedundantCheckOnNonNull(MethodBinding method, ASTNode location) {
+	String[] arguments = new String[] {new String(method.readableName())  };
+	this.handle(
+		IProblem.RedundantNullCheckOnNonNullMessageSend,
+		arguments,
+		arguments,
+		location.sourceStart,
+		location.sourceEnd);
+}
+
+public void missingNullAnnotationType(char[][] nullAnnotationName) {
+	String[] args = { new String(CharOperation.concatWith(nullAnnotationName, '.')) };
+	this.handle(IProblem.MissingNullAnnotationType, args, args, 0, 0);	
+}
+
+public void cannotImplementIncompatibleNullness(MethodBinding currentMethod, MethodBinding inheritedMethod) {
+	int sourceStart = 0, sourceEnd = 0;
+	if (this.referenceContext instanceof TypeDeclaration) {
+		sourceStart = ((TypeDeclaration) this.referenceContext).sourceStart;
+		sourceEnd =   ((TypeDeclaration) this.referenceContext).sourceEnd;
+	}
+	String[] problemArguments = {
+			new String(currentMethod.readableName()),
+			new String(currentMethod.declaringClass.readableName()),
+			new String(inheritedMethod.declaringClass.readableName())
+		};
+	String[] messageArguments = {
+			new String(currentMethod.shortReadableName()),
+			new String(currentMethod.declaringClass.shortReadableName()),
+			new String(inheritedMethod.declaringClass.shortReadableName())
+		};
+	this.handle(
+			IProblem.CannotImplementIncompatibleNullness,
+			problemArguments,
+			messageArguments,
+			sourceStart,
+			sourceEnd);
+}
+
+public void nullAnnotationNameMustBeQualified(char[][] typeName) {
+	String[] name = {new String(typeName[0])};
+	this.handle(IProblem.NullAnnotationNameMustBeQualified, name, name, 0, 0);
+}
+
+public void nullAnnotationIsRedundant(AbstractMethodDeclaration sourceMethod, int i) {
+	int sourceStart, sourceEnd;
+	if (i == -1) {
+		org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration decl = sourceMethod;
+		org.eclipse.jdt.internal.compiler.ast.MethodDeclaration methodDecl = (org.eclipse.jdt.internal.compiler.ast.MethodDeclaration) decl;
+		sourceStart = methodDecl.returnType.sourceStart;
+		if (methodDecl.annotations != null) {
+			// should have a @NonNull annotation, search for it:
+			for (int j=0; j<methodDecl.annotations.length; j++) {
+				if (methodDecl.annotations[j].resolvedType.id == TypeIds.T_ConfiguredAnnotationNonNull) {
+					sourceStart = methodDecl.annotations[j].sourceStart;
+					break;
+				}
+			}
+		}
+		sourceEnd = methodDecl.returnType.sourceEnd;
+	} else {
+		Argument arg = sourceMethod.arguments[i];
+		sourceStart = arg.declarationSourceStart;
+		sourceEnd = arg.sourceEnd;
+	}
+	this.handle(IProblem.RedundantNullAnnotation, ProblemHandler.NoArgument, ProblemHandler.NoArgument, sourceStart, sourceEnd);
+}
 }
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/problem/messages.properties	
+++ a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/problem/messages.properties	
@@ -653,6 +653,22 @@ 
 889 = Resource ''{0}'' should be managed by try-with-resource
 890 = Cannot switch on an enum value for source level below 1.5. Only convertible int values are permitted
 
+### NULL ANNOTATIONS
+910 = Type mismatch: required '@{0} {1}' but the provided value is null
+911 = Type mismatch: required '@{0} {1}' but the provided value can be null
+912 = Potential type mismatch: required '@{0} {1}' but nullness of the provided value is unknown
+913 = Buildpath problem: the type {0} which is configured as a null annotation type cannot be resolved
+914 = Cannot use the unqualified name ''{0}'' as an annotation name for null specification
+915 = The return type is incompatible with the @{1} return from {0}
+916 = Illegal redefinition of parameter {0}, inherited method from {1} declares this parameter as @{2}
+917 = Illegal redefinition of parameter {0}, inherited method from {1} does not constrain this parameter
+918 = Missing null annotation: inherited method from {1} declares this parameter as @{2}
+919 = Missing null annotation: inherited method from {1} declares this parameter as @{2}
+920 = Potential null pointer access: The method {0} may return null
+921 = Redundant null check: The method {0} cannot return null
+922 = The method {0} from class {1} cannot implement the corresponding method from type {2} due to incompatible nullness constraints
+923 = The nullness annotation is redundant with a default that applies to this location
+
 ### ELABORATIONS
 ## Access restrictions
 78592 = The type {1} is not accessible due to restriction on classpath entry {0}