### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java,v
retrieving revision 1.51
diff -u -r1.51 LoopingFlowContext.java
--- compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java	23 Aug 2010 08:41:25 -0000	1.51
+++ compiler/org/eclipse/jdt/internal/compiler/flow/LoopingFlowContext.java	5 Feb 2011 23:30:41 -0000
@@ -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
@@ -524,9 +524,13 @@
 				if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {
 					recordNullReference(local, reference, checkType);
 				}
-			} else if (! flowInfo.cannotBeDefinitelyNullOrNonNull(local)) {
+			} else if (flowInfo.cannotBeDefinitelyNullOrNonNull(local)) {
+				return; // no reason to complain
+			} else {
 				if (flowInfo.isPotentiallyNonNull(local)) {
 					recordNullReference(local, reference, CAN_ONLY_NON_NULL | checkType & CONTEXT_MASK);
+				} else if (flowInfo.isPotentiallyNull(local)) {
+					recordNullReference(local, reference, CAN_ONLY_NULL | checkType & CONTEXT_MASK);
 				} else {
 					if ((this.tagBits & FlowContext.HIDE_NULL_COMPARISON_WARNING) == 0) {
 						recordNullReference(local, reference, checkType);
#P org.eclipse.jdt.core.tests.compiler
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
retrieving revision 1.109
diff -u -r1.109 NullReferenceTest.java
--- src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java	19 Jan 2011 05:29:57 -0000	1.109
+++ src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java	5 Feb 2011 23:31:00 -0000
@@ -13832,4 +13832,21 @@
 			"}"},
 		"");
 }
+// Bug 336428 - [compiler][null] bogus warning "redundant null check" in condition of do {} while() loop
+public void testBug336428() {
+	this.runConformTest(
+		new String[] {
+	"DoWhileBug.java",
+			"public class DoWhileBug {\n" + 
+			"	void test(boolean b1, Object o1) {\n" + 
+			"		Object o2 = new Object();\n" + 
+			"		do {\n" +
+			"           if (b1)\n" + 
+			"				o1 = null;\n" + 
+			"		} while ((o2 = o1) != null);\n" + 
+			"	}\n" + 
+			"}"	
+		},
+		"");
+}
 }
\ No newline at end of file