### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: compiler/org/eclipse/jdt/internal/compiler/ast/CompoundAssignment.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/CompoundAssignment.java,v
retrieving revision 1.60
diff -u -r1.60 CompoundAssignment.java
--- compiler/org/eclipse/jdt/internal/compiler/ast/CompoundAssignment.java	22 Jul 2009 17:08:54 -0000	1.60
+++ compiler/org/eclipse/jdt/internal/compiler/ast/CompoundAssignment.java	9 Mar 2011 07:57:58 -0000
@@ -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
@@ -42,7 +42,17 @@
 	if (this.resolvedType.id != T_JavaLangString) {
 		this.lhs.checkNPE(currentScope, flowContext, flowInfo);
 	}
-	return  ((Reference) this.lhs).analyseAssignment(currentScope, flowContext, flowInfo, this, true).unconditionalInits();
+	flowInfo = ((Reference) this.lhs).analyseAssignment(currentScope, flowContext, flowInfo, this, true).unconditionalInits();
+	if (this.resolvedType.id == T_JavaLangString) {
+		LocalVariableBinding local = this.lhs.localVariableBinding();
+		if (local != null && this.resolvedType.id == T_JavaLangString) {
+			// compound assignment results in a definitely non null value for String
+			flowInfo.markAsDefinitelyNonNull(local);
+			if (flowContext.initsOnFinally != null)
+				flowContext.initsOnFinally.markAsDefinitelyNonNull(local);
+		}
+	}
+	return flowInfo;
 }
 
 	public boolean checkCastCompatibility() {