### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core.tests.model
Index: src/org/eclipse/jdt/core/tests/model/ClassFileTests.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/ClassFileTests.java,v
retrieving revision 1.29
diff -u -r1.29 ClassFileTests.java
--- src/org/eclipse/jdt/core/tests/model/ClassFileTests.java	20 Mar 2007 11:18:53 -0000	1.29
+++ src/org/eclipse/jdt/core/tests/model/ClassFileTests.java	26 Sep 2007 16:43:22 -0000
@@ -12,6 +12,7 @@
 
 import java.io.IOException;
 
+import org.eclipse.core.resources.IFolder;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
@@ -451,6 +452,38 @@
 }
 
 /*
+ * Ensures that if a root folder (that has a jar like name) is opened, and then a Jar package fragment root created on this root folder,
+ * then attempting to open a class file in this folder doesn't throw a ClassCastException
+ * (regression test for bug 204652 "Open Type": ClassCastException in conjunction with a class folder)
+ */
+public void testJarLikeRootFolder() throws CoreException {
+	try {
+		IJavaProject p = createJavaProject("P1", new String[0], new String[] {"/P1/classFolder.jar"}, "");
+		IFolder folder = createFolder("/P1/classFolder.jar/p");
+		createFile("/P1/classFolder.jar/X.class", "p");
+		
+		// populate cache with a valid package fragment root and a valid package fragment
+		IPackageFragment validPkg = p.getPackageFragmentRoot(folder.getParent()).getPackageFragment("p");
+		validPkg.open(null);
+
+		// create an invalid package fragment root and an invalid package fragment
+		IPackageFragment invalidPkg = p.getPackageFragmentRoot("/P1/classFolder.jar").getPackageFragment("p");
+		
+		// ensure that the class fille cannot be opened with a valid excepption
+		IClassFile openable = invalidPkg.getClassFile("X.class");
+		JavaModelException expected = null;
+		try {
+			openable.open(null);
+		} catch (JavaModelException e) {
+			expected = e;
+		}
+		assertExceptionEquals("Unexpected exception", "classFolder.jar [in P1] does not exist", expected);
+	} finally {
+		deleteProject("P1");
+	}
+}
+
+/*
  * Ensures that the parameter names of a binary method with source attached are correct.
  */
 public void testParameterNames01() throws CoreException {
#P org.eclipse.jdt.core
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
retrieving revision 1.125
diff -u -r1.125 PackageFragmentRoot.java
--- model/org/eclipse/jdt/internal/core/PackageFragmentRoot.java	21 Sep 2007 13:16:47 -0000	1.125
+++ model/org/eclipse/jdt/internal/core/PackageFragmentRoot.java	26 Sep 2007 16:43:23 -0000
@@ -324,7 +324,7 @@
 	if (!(o instanceof PackageFragmentRoot))
 		return false;
 	PackageFragmentRoot other = (PackageFragmentRoot) o;
-	return this.resource.equals(other.resource) && 
+	return getResource().equals(other.getResource()) && 
 			this.parent.equals(other.parent);
 }
 
@@ -441,8 +441,9 @@
 	}
 }		
 public String getElementName() {
-	if (this.resource instanceof IFolder)
-		return ((IFolder) this.resource).getName();
+	IResource res = getResource();
+	if (res instanceof IFolder)
+		return ((IFolder) res).getName();
 	return ""; //$NON-NLS-1$
 }
 /**
@@ -703,7 +704,7 @@
 }
 
 public int hashCode() {
-	return this.resource.hashCode();
+	return getResource().hashCode();
 }
 
 /**
Index: model/org/eclipse/jdt/internal/core/ClassFile.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/ClassFile.java,v
retrieving revision 1.136
diff -u -r1.136 ClassFile.java
--- model/org/eclipse/jdt/internal/core/ClassFile.java	21 Sep 2007 13:16:47 -0000	1.136
+++ model/org/eclipse/jdt/internal/core/ClassFile.java	26 Sep 2007 16:43:23 -0000
@@ -18,6 +18,7 @@
 
 import org.eclipse.core.resources.IContainer;
 import org.eclipse.core.resources.IFile;
+import org.eclipse.core.resources.IFolder;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
@@ -791,8 +792,14 @@
 	IStatus status = validateClassFile();
 	if (!status.isOK()) 
 		return status;
-	if (underlyingResource != null && !underlyingResource.isAccessible()) 
-		return newDoesNotExistStatus();
+	if (underlyingResource != null) {
+		if (!underlyingResource.isAccessible()) 
+			return newDoesNotExistStatus();
+		PackageFragmentRoot root;
+		if ((underlyingResource instanceof IFolder) && (root = getPackageFragmentRoot()).isArchive()) { // see https://bugs.eclipse.org/bugs/show_bug.cgi?id=204652
+			return root.newDoesNotExistStatus();
+		}
+	}
 	return JavaModelStatus.VERIFIED_OK;
 }
 }