Index: model/org/eclipse/jdt/internal/core/PackageFragmentRoot.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/PackageFragmentRoot.java,v
--- model/org/eclipse/jdt/internal/core/PackageFragmentRoot.java	27 Jun 2008 16:03:50 -0000	1.133
+++ model/org/eclipse/jdt/internal/core/PackageFragmentRoot.java	25 Nov 2008 10:16:38 -0000
@@ -454,7 +454,7 @@ 
  */
 protected void getHandleMemento(StringBuffer buff) {
 	IPath path;
-	IResource underlyingResource = resource();
+	IResource underlyingResource = getResource();
 	if (underlyingResource != null) {
 		// internal jar or regular root
 		if (resource().getProject().equals(getJavaProject().getProject())) {
Index: src/org/eclipse/jdt/core/tests/model/MementoTests.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/MementoTests.java,v
--- src/org/eclipse/jdt/core/tests/model/MementoTests.java	21 Aug 2008 10:15:28 -0000	1.26
+++ src/org/eclipse/jdt/core/tests/model/MementoTests.java	25 Nov 2008 10:16:39 -0000
@@ -13,8 +13,8 @@ 
 import java.io.File;
 
 import org.eclipse.core.resources.*;
-import org.eclipse.core.resources.IFolder;
 import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.Path;
 import org.eclipse.jdt.core.*;
 import org.eclipse.jdt.core.tests.util.Util;
 import org.eclipse.jdt.internal.core.JavaElement;
@@ -65,7 +65,9 @@ 
 		restored);
 }
 protected String getEscapedExternalJCLPath() {
-	String path = getExternalJCLPath().toString();
+	return getEscapedPath(getExternalJCLPath().toString());
+}
+protected String getEscapedPath(String path) {
 	StringBuffer buffer = new StringBuffer();
 	for (int i = 0; i < path.length(); i++) {
 		char character = path.charAt(i);
@@ -77,6 +79,12 @@ 
 public void setUpSuite() throws Exception {
 	super.setUpSuite();
 
+	Util.createClassFolder(new String[] {
+		"X.java",
+		"public class X {}"
+		}, 
+		getExternalResourcePath("myLib"), 
+		"1.4");
 	this.createJavaProject(
 			"P",
 			new String[] {"src"},
@@ -86,11 +94,13 @@ 
 				"/P/lib/myLib.jar",
 				"/OtherProj/lib",
 				"/OtherProj/lib/myLib.jar",
+				getExternalResourcePath("myLib")
 			},
 			"bin");
 }
 public void tearDownSuite() throws Exception {
 	this.deleteProject("P");
+	deleteExternalResource("myLib");
 	super.tearDownSuite();
 }
 /*
@@ -338,6 +348,15 @@ 
 		"=P/" + device + "\\/lib.jar<p(X.class",
 		classFile);
 }
+/*
+ * Ensures that a class file in an external library folder can be persisted and restored using its memento.
+ */
+public void testExternalLibraryFolderClassFileMemento() throws JavaModelException {
+	IClassFile classFile = getClassFile("P", getExternalResourcePath("myLib"), "", "X.class");
+	assertMemento(
+		"=P/" + getEscapedPath(new Path(getExternalResourcePath("myLib")).toString()) + "<(X.class",
+		classFile);
+}
 /**
  * Tests that an import declaration can be persisted and restored using its memento.
  */