### 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	17 Mar 2011 06:11:47 -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;
@@ -304,7 +305,7 @@
 					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)
@@ -323,6 +324,26 @@
 							null, // inside original project
 							false, // don't retrieve exported roots
 							null); /*no reverse map*/
+						// https://bugs.eclipse.org/bugs/show_bug.cgi?id=335986
+						// When a package fragment's corresponding resource is removed from the project, 
+						// IJavaProject#computePackageFragmentRoots() doesn't include that entry. Hence 
+						// the cache become necessary in such cases. Add the cache to the accumulatedRoots 
+						// only when it's not already present.
+						RootInfo rootInfo = (RootInfo) state.oldRoots.get(this.oldResolvedClasspath[i].getPath());
+						if (rootInfo != null && rootInfo.cache != null) {
+							IPackageFragmentRoot oldRoot = rootInfo.cache;
+							boolean found = false;
+							for (int j = 0; j < accumulatedRoots.size(); j++) {
+								IPackageFragmentRoot root = (IPackageFragmentRoot) accumulatedRoots.elementAt(j);
+								if (!root.getPath().equals(oldRoot.getPath())) {
+									found = true;
+									break;
+								}
+							}
+							if (!found)
+								accumulatedRoots.add(oldRoot);
+						}
+
 						pkgFragmentRoots = new PackageFragmentRoot[accumulatedRoots.size()];
 						accumulatedRoots.copyInto(pkgFragmentRoots);
 					} catch (JavaModelException e) {
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 1.342
diff -u -r1.342 DeltaProcessor.java
--- model/org/eclipse/jdt/internal/core/DeltaProcessor.java	4 Mar 2011 13:54:41 -0000	1.342
+++ model/org/eclipse/jdt/internal/core/DeltaProcessor.java	17 Mar 2011 06:11:47 -0000
@@ -105,26 +105,35 @@
 		IPath rootPath;
 		int entryKind;
 		IPackageFragmentRoot root;
+		IPackageFragmentRoot cache;
 		RootInfo(JavaProject project, IPath rootPath, char[][] inclusionPatterns, char[][] exclusionPatterns, int entryKind) {
 			this.project = project;
 			this.rootPath = rootPath;
 			this.inclusionPatterns = inclusionPatterns;
 			this.exclusionPatterns = exclusionPatterns;
 			this.entryKind = entryKind;
+			this.cache = getPackageFragmentRoot();
+		}
+		public 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());
-					}
+					this.root = getPackageFragmentRoot();
 				}
 			}
+			if (this.root != null) 
+				this.cache = this.root;
 			return this.root;
 		}
 		boolean isRootOfProject(IPath path) {
#P org.eclipse.jdt.core.tests.model
Index: src/org/eclipse/jdt/core/tests/model/JavaElementDeltaTests.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/JavaElementDeltaTests.java,v
retrieving revision 1.97
diff -u -r1.97 JavaElementDeltaTests.java
--- src/org/eclipse/jdt/core/tests/model/JavaElementDeltaTests.java	30 Nov 2010 15:06:52 -0000	1.97
+++ src/org/eclipse/jdt/core/tests/model/JavaElementDeltaTests.java	17 Mar 2011 06:11:50 -0000
@@ -2432,7 +2432,8 @@
 		setClasspath(p, new IClasspathEntry[] {});
 		assertDeltas(
 			"Unexpected delta",
-			"P[*]: {CONTENT | RAW CLASSPATH CHANGED | RESOLVED CLASSPATH CHANGED}\n" +
+			"P[*]: {CHILDREN | CONTENT | RAW CLASSPATH CHANGED | RESOLVED CLASSPATH CHANGED}\n" + 
+			"	"+ getExternalPath() + "externalLib[*]: {REMOVED FROM CLASSPATH}\n" + 
 			"	ResourceDelta(/P/.classpath)[*]"
 		);
 	} finally {
@@ -2523,7 +2524,8 @@
 		setClasspath(p, new IClasspathEntry[] {});
 		assertDeltas(
 			"Unexpected delta",
-			"P[*]: {CONTENT | RAW CLASSPATH CHANGED | RESOLVED CLASSPATH CHANGED}\n" +
+			"P[*]: {CHILDREN | CONTENT | RAW CLASSPATH CHANGED | RESOLVED CLASSPATH CHANGED}\n" + 
+			"	"+ getExternalPath() + "externalLib.abc[*]: {REMOVED FROM CLASSPATH}\n" + 
 			"	ResourceDelta(/P/.classpath)[*]"		);
 	} finally {
 		stopDeltas();