Bug 22164 Referencing JavaPlugin class in earlyStartup causes invalid thread access [misc]
It is possible that this is not a bug, either because it's known & not supported to because it's internal API, but it was rather unexpected, bizzare behavor. I have a plugin which depends on JDT-UI. This plugin also happens to implement IStartup. If at anypoint, I load the org.eclipse.jdt.internal.ui.JavaPlugin class from earlyStartup(), the Plugin loader attempts to load JDT-UI, which then promptly bombs out with invalid thread access and fails to load. This only happens if no JDT UI perspectives are loaded (in other words, on a fresh workspace). I will attach a simple plugin that demonstrates the problem. Just run it on a fresh workspace. The line it fails on seems to be "manager.registerAdapters(new JavaElementAdapterFactory(), IJavaElement.class);" in the startup() method. Thanks, Andrew
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/viewsupport/JavaElementImageProvider.java
return getWorkbenchImageDescriptor((IAdaptable) element, flags);
		}
		return null;
	}
	
	private static boolean showOverlayIcons(int flags) {
		return (flags & OVERLAY_ICONS) != 0;
	}
		
	private static boolean useSmallSize(int flags) {
		return (flags & SMALL_ICONS) != 0;
	}
	
	private static boolean useLightIcons(int flags) {
		return (flags & LIGHT_TYPE_ICONS) != 0;
	}	
	/**
	 * Returns an image descriptor for a compilatio unit not on the class path.
	 * The descriptor includes overlays, if specified.
	 */
	public ImageDescriptor getCUResourceImageDescriptor(IFile file, int flags) {
		Point size= useSmallSize(flags) ? SMALL_SIZE : BIG_SIZE;
		return new JavaElementImageDescriptor(JavaPluginImages.DESC_OBJS_CUNIT_RESOURCE, 0, size);
	}	
		
	/**
	 * Returns an image descriptor for a java element. The descriptor includes overlays, if specified.
	 */
	public ImageDescriptor getJavaImageDescriptor(IJavaElement element, int flags) {
		int adornmentFlags= computeJavaAdornmentFlags(element, flags);