fix ClasspathComputer: ignore if oldEntry not found #820

fixes random failing ClasspathUpdaterTest

#820

Author: Jörg Kubitz

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/ClasspathComputer.java

@@ -34,6 +34,7 @@
 import org.eclipse.jdt.core.IClasspathAttribute;
 import org.eclipse.jdt.core.IClasspathEntry;
 import org.eclipse.jdt.core.IJavaModelStatus;
+import org.eclipse.jdt.core.IJavaModelStatusConstants;
 import org.eclipse.jdt.core.IJavaProject;
 import org.eclipse.jdt.core.IPackageFragmentRoot;
 import org.eclipse.jdt.core.JavaConventions;
@@ -267,17 +268,23 @@ private static void addLibraryEntry(IPluginLibrary library, Map<String, IPath> s
 
 		IPackageFragmentRoot root = context.javaProject.getPackageFragmentRoot(jarFile);
 		if (root.exists() && root.getKind() == IPackageFragmentRoot.K_BINARY) {
-			IClasspathEntry oldEntry = root.getRawClasspathEntry();
-			// If we have the same binary root but new or different source, we
-			// should recreate the entry. That is when the source attachment:
-			// - is not defined: the default could be available now, or
-			// - is overridden with a different value.
-			if ((sourceAttachment == null && oldEntry.getSourceAttachmentPath() != null)
-					|| (sourceAttachment != null && sourceAttachment.equals(oldEntry.getSourceAttachmentPath()))) {
-				context.reloaded.add(oldEntry);
-				return;
+			try {
+				IClasspathEntry oldEntry = root.getRawClasspathEntry();
+				// If we have the same binary root but new or different source, we
+				// should recreate the entry. That is when the source attachment:
+				// - is not defined: the default could be available now, or
+				// - is overridden with a different value.
+				if ((sourceAttachment == null && oldEntry.getSourceAttachmentPath() != null)
+						|| (sourceAttachment != null && sourceAttachment.equals(oldEntry.getSourceAttachmentPath()))) {
+					context.reloaded.add(oldEntry);
+					return;
+				}
+				isExported = oldEntry.isExported();
+			} catch (JavaModelException e) {
+				if (e.getStatus().getCode() != IJavaModelStatusConstants.ELEMENT_NOT_ON_CLASSPATH) {
+					throw e;
+				}
 			}
-			isExported = oldEntry.isExported();
 		}
 		reloadClasspathEntry(jarFile, name, sourceAttachment, isExported, context);
 	}