SWT No More Handles - in Windows 7

Question

I'm working on an old RCP application that mysteriously stopped working, according to the client. After much frustration, I finally got a hold of the original developer's computer (an XP machine). It runs fine on that computer, nice.

So I compile it and put it on another XP machine, and it runs fine.

Run it on a Windows 7 machine, and it shows the splashscreen, then the main UI for a split second before closing.

So I copied the Eclipse work environment for that project over to the Windows 7 machine, and it gives me the same behavior, plus the error message:

 org.eclipse.swt.SWTError: No more handles

Apparently, Sleak is supposed to be the answer for memory leaks, but it also lasts only a split second before the whole program dies. I don't think it's a memory leak; only two views are opened on startup. Is there something in Windows 7 that might be restricting the handles?

Here is the full error message:

 org.eclipse.swt.SWTError: No more handles
at org.eclipse.swt.SWT.error(SWT.java:3803)
at org.eclipse.swt.SWT.error(SWT.java:3695)
at org.eclipse.swt.SWT.error(SWT.java:3666)
at org.eclipse.swt.graphics.Image.<init>(Image.java:730)
at org.eclipse.jface.resource.FileImageDescriptor.createImage(FileImageDescriptor.java:176)
at org.eclipse.jface.resource.ImageDescriptor.createImage(ImageDescriptor.java:227)
at org.eclipse.jface.resource.ImageDescriptor.createImage(ImageDescriptor.java:205)
at org.eclipse.gef.ui.palette.editparts.PaletteEditPart$ImageCache.getImage(PaletteEditPart.java:396)
at org.eclipse.gef.ui.palette.editparts.PaletteEditPart.setImageDescriptor(PaletteEditPart.java:353)
at org.eclipse.gef.internal.ui.palette.editparts.ToolEntryEditPart.refreshVisuals(ToolEntryEditPart.java:455)
at org.eclipse.gef.editparts.AbstractEditPart.refresh(AbstractEditPart.java:676)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.refresh(AbstractGraphicalEditPart.java:571)
at org.eclipse.gef.editparts.AbstractEditPart.addNotify(AbstractEditPart.java:235)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.addNotify(AbstractGraphicalEditPart.java:219)
at org.eclipse.gef.editparts.AbstractEditPart.addChild(AbstractEditPart.java:198)
at org.eclipse.gef.editparts.AbstractEditPart.refreshChildren(AbstractEditPart.java:727)
at org.eclipse.gef.editparts.AbstractEditPart.refresh(AbstractEditPart.java:677)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.refresh(AbstractGraphicalEditPart.java:571)
at org.eclipse.gef.editparts.AbstractEditPart.addNotify(AbstractEditPart.java:235)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.addNotify(AbstractGraphicalEditPart.java:219)
at org.eclipse.gef.editparts.AbstractEditPart.addChild(AbstractEditPart.java:198)
at org.eclipse.gef.editparts.AbstractEditPart.refreshChildren(AbstractEditPart.java:727)
at org.eclipse.gef.editparts.AbstractEditPart.refresh(AbstractEditPart.java:677)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.refresh(AbstractGraphicalEditPart.java:571)
at org.eclipse.gef.editparts.AbstractEditPart.addNotify(AbstractEditPart.java:235)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.addNotify(AbstractGraphicalEditPart.java:219)
at org.eclipse.gef.editparts.AbstractEditPart.addChild(AbstractEditPart.java:198)
at org.eclipse.gef.editparts.SimpleRootEditPart.setContents(SimpleRootEditPart.java:101)
at org.eclipse.gef.ui.palette.PaletteViewer.setPaletteRoot(PaletteViewer.java:397)
at org.eclipse.gef.EditDomain.setPaletteViewer(EditDomain.java:360)
at org.eclipse.gef.ui.palette.PaletteViewerProvider.hookPaletteViewer(PaletteViewerProvider.java:76)
at org.eclipse.gef.ui.palette.PaletteViewerProvider.createPaletteViewer(PaletteViewerProvider.java:59)
at org.eclipse.gef.ui.views.palette.PaletteViewerPage.createControl(PaletteViewerPage.java:63)
at org.eclipse.gef.ui.views.palette.PaletteView.doCreatePage(PaletteView.java:100)
at org.eclipse.ui.part.PageBookView.createPage(PageBookView.java:399)
at org.eclipse.ui.part.PageBookView.partActivated(PageBookView.java:741)
at org.eclipse.ui.internal.PartListenerList$1.run(PartListenerList.java:72)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.runtime.Platform.run(Platform.java:880)
at org.eclipse.ui.internal.PartListenerList.fireEvent(PartListenerList.java:57)
at org.eclipse.ui.internal.PartListenerList.firePartActivated(PartListenerList.java:70)
at org.eclipse.ui.internal.PartService.firePartActivated(PartService.java:186)
at org.eclipse.ui.internal.PartService.setActivePart(PartService.java:305)
at org.eclipse.ui.internal.WorkbenchPagePartList.fireActivePartChanged(WorkbenchPagePartList.java:56)
at org.eclipse.ui.internal.PartList.setActivePart(PartList.java:126)
at org.eclipse.ui.internal.WorkbenchPage.setActivePart(WorkbenchPage.java:3491)
at org.eclipse.ui.internal.WorkbenchPage.activate(WorkbenchPage.java:610)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2832)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:2729)
at org.eclipse.ui.internal.WorkbenchPage.access$11(WorkbenchPage.java:2721)
at org.eclipse.ui.internal.WorkbenchPage$10.run(WorkbenchPage.java:2673)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2668)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2652)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2635)
at org.eclipse.ui.ide.IDE.openEditor(IDE.java:708)
at [companyname].gef.ApplicationWorkbenchWindowAdvisor.postWindowOpen(ApplicationWorkbenchWindowAdvisor.java:111)
at org.eclipse.ui.internal.WorkbenchWindow.fireWindowOpened(WorkbenchWindow.java:1229)
at org.eclipse.ui.internal.WorkbenchWindow.open(WorkbenchWindow.java:786)
at org.eclipse.ui.internal.Workbench$22.runWithException(Workbench.java:1043)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:133)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3800)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3425)
at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
at org.eclipse.ui.internal.Workbench$27.runWithException(Workbench.java:1363)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:133)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3800)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3425)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2295)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2200)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:495)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:288)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:490)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at [companyname].gef.Application.start(Application.java:28)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:193)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:386)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:549)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:504)
at org.eclipse.equinox.launcher.Main.run(Main.java:1236)
at org.eclipse.equinox.launcher.Main.main(Main.java:1212)

Answer 1

I've had this a number of times, it's related to disposing of resources. You may be creating Font, Image objects and not releasing them by explicitly calling .dispose(). I doubt it's related to Windows 7, it would happen there too but might take longer to happen as you might have more system resources available on that machine. Making sure you track and dispose of your allocated resources normally solves the problem.

Answer 2

If something works fine on Win XP and doesn't work on Win 7, then its potentially an SWT bug. I suggest you raise a bug in the Eclipse bugzilla.