Bug 59211 NPE from RemoveFromClasspathAction when double clicking on a new jar in a ClasspathContainer
I have written an IClasspathContainer with an Initializer to sync the classpath with an external file. When the file I am monitoring changes the contents of the container is updated with the new jars, but when I double click on the jar to see the contents I get the following exception: java.lang.NullPointerException at org.eclipse.jdt.ui.actions.RemoveFromClasspathAction.canRemove(RemoveFromClasspathAction.java:134) at org.eclipse.jdt.ui.actions.RemoveFromClasspathAction.checkEnabled(RemoveFromClasspathAction.java:78) at org.eclipse.jdt.ui.actions.RemoveFromClasspathAction.selectionChanged(RemoveFromClasspathAction.java:71) at org.eclipse.jdt.ui.actions.SelectionDispatchAction.dispatchSelectionChanged(SelectionDispatchAction.java:200) at org.eclipse.jdt.ui.actions.SelectionDispatchAction.selectionChanged(SelectionDispatchAction.java:195) at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:159) at org.eclipse.core.internal.runtime.InternalPlatform.run(InternalPlatform.java(Inlined Compiled Code)) at org.eclipse.core.runtime.Platform.run(Platform.java(Compiled Code)) at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:157) at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:1310) at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:666) at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:690) at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:178) at org.eclipse.jface.util.OpenStrategy.access$3(OpenStrategy.java:173) at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:309) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java(Compiled Code)) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java(Inlined Compiled Code)) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java(Compiled Code)) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java(Compiled Code)) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java(Compiled Code)) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1536) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:257) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:139) at org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:90) at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:277) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:239) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:117) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:79) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:41) at java.lang.reflect.Method.invoke(Method.java:371) at org.eclipse.core.launcher.Main.basicRun(Main.java:267) at org.eclipse.core.launcher.Main.run(Main.java:692) at org.eclipse.core.launcher.Main.main(Main.java:676) As another point if I click the + button by the jar the + symbol disappears and I don't see any error. After restarting eclipse the jar's contents is correctly displayed.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/RemoveFromClasspathAction.java
import java.util.List;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRunnable;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IWorkbenchSite;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.help.WorkbenchHelp;
import org.eclipse.jdt.core.IClasspathEntry;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.internal.ui.IJavaHelpContextIds;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.actions.WorkbenchRunnableAdapter;
import org.eclipse.jdt.internal.ui.util.ExceptionHandler;
import org.eclipse.jdt.internal.ui.actions.ActionMessages;
/**
 * Action to remove package fragment roots from the classpath of its parent
 * project. Currently, the action is applicable to selections containing
 * not-external archives (JAR or zip).
 * 
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * 
 * @since 2.1
 */
public class RemoveFromClasspathAction extends SelectionDispatchAction {