Bug 307405 [CommonNavigator] Deadlock in NavigatorContentServiceContentProvider
We are using an adopting product and one of our users encountered this deadlock when starting up their workspace: 1LKDEADLOCK Deadlock detected !!! NULL --------------------- NULL 2LKDEADLOCKTHR Thread "main" (0x41591300) 3LKDEADLOCKWTR is waiting for: 4LKDEADLOCKMON sys_mon_t:0x43134548 infl_mon_t: 0x43134580: 4LKDEADLOCKOBJ org/eclipse/ui/internal/navigator/NavigatorSaveablesService@0x05DB48A8/0x05DB48B4: 3LKDEADLOCKOWN which is owned by: 2LKDEADLOCKTHR Thread "Framework Event Dispatcher" (0x42467700) 3LKDEADLOCKWTR which is waiting for: 4LKDEADLOCKMON sys_mon_t:0x43BA6AB8 infl_mon_t: 0x43BA6AF0: 4LKDEADLOCKOBJ org/eclipse/ui/internal/navigator/NavigatorContentServiceContentProvider@0x0306F6E8/0x0306F6F4: 3LKDEADLOCKOWN which is owned by: 2LKDEADLOCKTHR Thread "main" (0x41591300) I will attach the stack trace.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentServiceContentProvider.java
if (theOverridingExtensions[i].internalGetContentProvider().isPipelined()) {
				pipelinedContentProvider = (IPipelinedTreeContentProvider) theOverridingExtensions[i]
						.internalGetContentProvider();
				aSuggestedParent = pipelinedContentProvider.getPipelinedParent(anInputElement, aSuggestedParent);
				overridingExtensions = theOverridingExtensions[i]
						.getOverridingExtensionsForTriggerPoint(anInputElement);
				if (overridingExtensions.length > 0) {
					aSuggestedParent = pipelineParent(anInputElement, overridingExtensions, aSuggestedParent);
				}
			}
		}
		return aSuggestedParent != null ? aSuggestedParent : theCurrentParent;
	}
	/**
	 * Calculate hasChildren for both an element or a path.
	 * 
	 *  If any of the first class NCEs don't implement the IPipelinedTreeContentProviderHasChildren 
	 *  and they return true, then we have to use that as the value, as we are obliged to take
	 *  the union of the non-pipelined calls. This may result in a false positive hasChildren
	 *  indication if the pipeline mechanism does not actually contribute children later.
	 *  For pipelined calls, we simply ask the pipelined content provider about the children
	 *  and they can override this as they would in the case where they are providing the objects.
	 */
	public synchronized boolean hasChildren(Object anElementOrPath) {
		Object anElement = internalAsElement(anElementOrPath);
		Set enabledExtensions = contentService.findContentExtensionsByTriggerPoint(anElement);
		NavigatorContentExtension ext;
		boolean suggestedHasChildren = false;
		for (Iterator itr = enabledExtensions.iterator(); itr.hasNext();) {
			ext = (NavigatorContentExtension) itr.next();