Bug 11748 switch to new DecoratorManager API
From the workbench change notes: API changes IWorkbenchPartSite.getDecoratorManager() - As the DecoratorManager has proven to be required for more than just IWorkbenchPartSites we have moved getDecoratorManager() to IWorkbench and deprecated the getDecoratorManager() in IWorkbenchPartSite. The one in IWorkbenchPartSite will be removed after the other Eclipse components have had a chance to switch to the new API.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
return JavaCore.create(((IWorkspace)input).getRoot());
		} else if (input instanceof IContainer) {
			return JavaCore.create((IContainer)input);
		}
		
		
		
		return JavaCore.create(JavaPlugin.getWorkspace().getRoot());	
	}
	
	/**
	 * Answer the property defined by key.
	 */
	public Object getAdapter(Class key) {
		if (key.equals(ISelectionProvider.class))
			return fViewer;
		return super.getAdapter(key);
	}
	/**
	 * Returns the tool tip text for the given element.
	 */
	String getToolTipText(Object element) {
		String result;
		if (!(element instanceof IResource)) {
			result= JavaElementLabels.getTextLabel(element, StandardJavaUILabelProvider.DEFAULT_TEXTFLAGS);		
		} else {
			IPath path= ((IResource) element).getFullPath();
			if (path.isRoot()) {
				result= PackagesMessages.getString("PackageExplorer.title"); 
			} else {