Index: compiler/org/eclipse/jdt/internal/compiler/flow/FlowContext.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/FlowContext.java,v
--- compiler/org/eclipse/jdt/internal/compiler/flow/FlowContext.java	7 Mar 2009 00:59:06 -0000	1.61
+++ compiler/org/eclipse/jdt/internal/compiler/flow/FlowContext.java	15 Jan 2010 06:38:10 -0000
@@ -1,5 +1,5 @@ 
 /*******************************************************************************
- * Copyright (c) 2000, 2009 IBM Corporation and others.
+ * Copyright (c) 2000, 2010 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
@@ -556,12 +556,27 @@ 
 		case CAN_ONLY_NULL | IN_COMPARISON_NON_NULL:
 		case CAN_ONLY_NULL | IN_ASSIGNMENT:
 		case CAN_ONLY_NULL | IN_INSTANCEOF:
+			TypeBinding compileTimeType = reference.resolvedType;
 			if (flowInfo.isDefinitelyNull(local)) {
 				switch(checkType & CONTEXT_MASK) {
 					case FlowContext.IN_COMPARISON_NULL:
+						if (!compileTimeType.isBaseType() && ((checkType & CHECK_MASK) == CAN_ONLY_NULL)) { // check for auto-unboxing first and report appropriate warning
+							TypeBinding unboxedType = scope.environment().computeBoxingType(compileTimeType);
+							if (unboxedType != null && unboxedType != compileTimeType) {
+								scope.problemReporter().localVariableNullReference(local, reference);
+								return;
+							}
+						}
 						scope.problemReporter().localVariableRedundantCheckOnNull(local, reference);
 						return;
 					case FlowContext.IN_COMPARISON_NON_NULL:
+						if (!compileTimeType.isBaseType()  && ((checkType & CHECK_MASK) == CAN_ONLY_NULL)) { // check for auto-unboxing first and report appropriate warning
+							TypeBinding unboxedType = scope.environment().computeBoxingType(compileTimeType);
+							if (unboxedType != null && unboxedType != compileTimeType) {
+								scope.problemReporter().localVariableNullReference(local, reference);
+								return;
+							}
+						}
 						scope.problemReporter().localVariableNullComparedToNonNull(local, reference);
 						return;
 					case FlowContext.IN_ASSIGNMENT:
@@ -571,6 +586,27 @@ 
 						scope.problemReporter().localVariableNullInstanceof(local, reference);
 						return;
 				}
+			} else if (flowInfo.isPotentiallyNull(local)) {
+				switch(checkType & CONTEXT_MASK) {
+					case FlowContext.IN_COMPARISON_NULL:
+						if (!compileTimeType.isBaseType()  && ((checkType & CHECK_MASK) == CAN_ONLY_NULL)) { // check for auto-unboxing first and report appropriate warning
+							TypeBinding unboxedType = scope.environment().computeBoxingType(compileTimeType);
+							if (unboxedType != null && unboxedType != compileTimeType) {
+								scope.problemReporter().localVariablePotentialNullReference(local, reference);
+								return;
+							}
+						}
+						break;
+					case FlowContext.IN_COMPARISON_NON_NULL:
+						if (!compileTimeType.isBaseType()  && ((checkType & CHECK_MASK) == CAN_ONLY_NULL)) { // check for auto-unboxing first and report appropriate warning
+							TypeBinding unboxedType = scope.environment().computeBoxingType(compileTimeType);
+							if (unboxedType != null && unboxedType != compileTimeType) {
+								scope.problemReporter().localVariablePotentialNullReference(local, reference);
+								return;
+							}
+						}
+						break;
+					}
 			} else if (flowInfo.cannotBeDefinitelyNullOrNonNull(local)) {
 				return;
 			}
Index: src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java,v
--- src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java	19 Nov 2009 15:57:22 -0000	1.83
+++ src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java	15 Jan 2010 06:38:17 -0000
@@ -1,5 +1,5 @@ 
 /*******************************************************************************
- * Copyright (c) 2005, 2009 IBM Corporation and others.
+ * Copyright (c) 2005, 2010 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
@@ -12,9 +12,10 @@ 
 
 import java.util.Map;
 
+import junit.framework.Test;
+
 import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
 import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
-import junit.framework.Test;
 
 /* See also NullReferenceImplTests for low level, implementation dependent
  * tests. */
@@ -10328,4 +10329,81 @@ 
 				"----------\n");
 	}
 }
+
+// https://bugs.eclipse.org/bugs/show_bug.cgi?id=253896
+// Test whether Null pointer access warnings are being reported correctly when auto-unboxing
+public void testBug253896a() {
+	if (this.complianceLevel >= ClassFileConstants.JDK1_5) {
+		this.runNegativeTest(
+				new String[] {
+						"X.java",
+						"public class X {\n" +
+						"  public void foo() {\n" +
+						"    Integer f1 = null;\n" +
+						"	 if(f1 == 1)\n" +
+						" 	 	System.out.println(\"f1 is 1\");\n" +
+						"    Integer f2 = null;\n" +
+						"	 int abc = (f2 != 1)? 1 : 0;\n" +
+						"    Float f3 = null;\n" +
+						"	 if(f3 == null)\n" +
+						" 	 	System.out.println(\"i1 is null\");\n" +
+						"    Byte f4 = null;\n" +
+						"	 if(f4 != null)\n" +
+						" 	 	System.out.println(\"i2 is not null\");\n" +
+						"  }\n" +
+						"}"},
+				"----------\n" +
+				"1. ERROR in X.java (at line 4)\n" +
+				"	if(f1 == 1)\n" +
+				"	   ^^\n" +
+				"Null pointer access: The variable f1 can only be null at this location\n" +
+				"----------\n" +
+				"2. ERROR in X.java (at line 7)\n" +
+				"	int abc = (f2 != 1)? 1 : 0;\n" +
+				"	           ^^\n" +
+				"Null pointer access: The variable f2 can only be null at this location\n" +
+				"----------\n" +
+				"3. ERROR in X.java (at line 9)\n" +
+				"	if(f3 == null)\n" +
+				"	   ^^\n" +
+				"Redundant null check: The variable f3 can only be null at this location\n" +
+				"----------\n" +
+				"4. ERROR in X.java (at line 12)\n" +
+				"	if(f4 != null)\n" +
+				"	   ^^\n" +
+				"Null comparison always yields false: The variable f4 can only be null at this location\n" +
+				"----------\n");
+	}
+}
+
+// https://bugs.eclipse.org/bugs/show_bug.cgi?id=253896
+// To test whether null pointer access and potential null pointer access warnings are correctly reported when auto-unboxing
+public void testBug253896b() {
+	if (this.complianceLevel >= ClassFileConstants.JDK1_5) {
+		this.runNegativeTest(
+				new String[] {
+						"X.java",
+						"public class X {\n" +
+						"  public void foo(Integer i1, Integer i2) {\n" +
+						"	 if(i1 == null && i2 == null){\n" +
+						"		if(i1 == 1)\n" +
+						" 	 	System.out.println(i1);}\n" +	//i1 is definitely null here
+						"	 else {\n" +
+						"		if(i1 == 0) {}\n" +		//i1 may be null here.
+						"	 }\n" +
+						"  }\n" +
+						"}"},
+				"----------\n" +
+				"1. ERROR in X.java (at line 4)\n" +
+				"	if(i1 == 1)\n" +
+				"	   ^^\n" +
+				"Null pointer access: The variable i1 can only be null at this location\n" +
+				"----------\n" +
+				"2. ERROR in X.java (at line 7)\n" +
+				"	if(i1 == 0) {}\n" +
+				"	   ^^\n" +
+				"Potential null pointer access: The variable i1 may be null at this location\n" +
+				"----------\n");
+	}
+}
 }