### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: model/org/eclipse/jdt/internal/core/ClasspathChange.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/ClasspathChange.java,v
retrieving revision 1.25
diff -u -r1.25 ClasspathChange.java
--- model/org/eclipse/jdt/internal/core/ClasspathChange.java	23 Jun 2009 05:40:04 -0000	1.25
+++ model/org/eclipse/jdt/internal/core/ClasspathChange.java	25 Feb 2011 09:07:47 -0000
@@ -28,6 +28,7 @@
 import org.eclipse.jdt.core.IPackageFragmentRoot;
 import org.eclipse.jdt.core.JavaModelException;
 import org.eclipse.jdt.internal.compiler.util.ObjectVector;
+import org.eclipse.jdt.internal.core.DeltaProcessor.RootInfo;
 import org.eclipse.jdt.internal.core.JavaModelManager.PerProjectInfo;
 import org.eclipse.jdt.internal.core.search.indexing.IndexManager;
 import org.eclipse.jdt.internal.core.util.Util;
@@ -304,13 +305,22 @@
 					result |= HAS_LIBRARY_CHANGE;
 				}
 
-				PackageFragmentRoot[] pkgFragmentRoots = null;
+				IPackageFragmentRoot[] pkgFragmentRoots = null;
 				if (removedRoots != null) {
 					PackageFragmentRoot oldRoot = (PackageFragmentRoot)  removedRoots.get(this.oldResolvedClasspath[i].getPath());
 					if (oldRoot != null) { // use old root if any (could be none if entry wasn't bound)
 						pkgFragmentRoots = new PackageFragmentRoot[] { oldRoot };
 					}
 				}
+				else {
+					// https://bugs.eclipse.org/bugs/show_bug.cgi?id=335986
+					// When removedRoots doesn't have the package fragment roots, recover them from the cache 
+					RootInfo rootInfo = (RootInfo)state.oldRoots.get(this.oldResolvedClasspath[i].getPath());
+					if (rootInfo != null && rootInfo.cache != null) {
+						IPackageFragmentRoot oldRoot = rootInfo.cache;
+						pkgFragmentRoots = new IPackageFragmentRoot[] { oldRoot };
+					}
+				}
 				if (pkgFragmentRoots == null) {
 					try {
 						ObjectVector accumulatedRoots = new ObjectVector();
Index: model/org/eclipse/jdt/internal/core/DeltaProcessor.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/DeltaProcessor.java,v
retrieving revision 1.338.2.1
diff -u -r1.338.2.1 DeltaProcessor.java
--- model/org/eclipse/jdt/internal/core/DeltaProcessor.java	13 Dec 2010 16:16:13 -0000	1.338.2.1
+++ model/org/eclipse/jdt/internal/core/DeltaProcessor.java	25 Feb 2011 09:07:53 -0000
@@ -102,6 +102,7 @@
 		public JavaProject project;
 		IPath rootPath;
 		int entryKind;
+		IPackageFragmentRoot cache;
 		IPackageFragmentRoot root;
 		RootInfo(JavaProject project, IPath rootPath, char[][] inclusionPatterns, char[][] exclusionPatterns, int entryKind) {
 			this.project = project;
@@ -109,19 +110,24 @@
 			this.inclusionPatterns = inclusionPatterns;
 			this.exclusionPatterns = exclusionPatterns;
 			this.entryKind = entryKind;
+			this.cache = getPackageFragmentRoot();
+		}
+		private IPackageFragmentRoot getPackageFragmentRoot(){
+			IPackageFragmentRoot tRoot = null;
+			Object target = JavaModel.getTarget(this.rootPath, false/*don't check existence*/);
+			if (target instanceof IResource) {
+				tRoot = this.project.getPackageFragmentRoot((IResource)target);
+			} else {
+				tRoot = this.project.getPackageFragmentRoot(this.rootPath.toOSString());
+			}
+			return tRoot;
 		}
 		public IPackageFragmentRoot getPackageFragmentRoot(IResource resource) {
 			if (this.root == null) {
-				if (resource != null) {
-					this.root = this.project.getPackageFragmentRoot(resource);
-				} else {
-					Object target = JavaModel.getTarget(this.rootPath, false/*don't check existence*/);
-					if (target instanceof IResource) {
-						this.root = this.project.getPackageFragmentRoot((IResource)target);
-					} else {
-						this.root = this.project.getPackageFragmentRoot(this.rootPath.toOSString());
-					}
+				if (resource == null) {
+					return this.cache;
 				}
+				this.root = this.project.getPackageFragmentRoot(resource);
 			}
 			return this.root;
 		}