Bug 29165 exception when deleting a class in I20030107 (win2k)
steps to reproduce the exception : - selected class in package explorer - selected delete in contextmenu
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/JavaPlugin.java
if (window == null)
			return null;
		return getWorkbench().getActiveWorkbenchWindow().getActivePage();
	}
		
	public synchronized CompilationUnitDocumentProvider getCompilationUnitDocumentProvider() {
		if (fCompilationUnitDocumentProvider == null)
			fCompilationUnitDocumentProvider= new CompilationUnitDocumentProvider();
		return fCompilationUnitDocumentProvider;
	}
	
	public synchronized ClassFileDocumentProvider getClassFileDocumentProvider() {
		if (fClassFileDocumentProvider == null)
			fClassFileDocumentProvider= new ClassFileDocumentProvider();
		return fClassFileDocumentProvider;
	}
	public synchronized IWorkingCopyManager getWorkingCopyManager() {
		return getCompilationUnitDocumentProvider();
	}
	
	public synchronized ProblemMarkerManager getProblemMarkerManager() {
		if (fProblemMarkerManager == null)
			fProblemMarkerManager= new ProblemMarkerManager();
		return fProblemMarkerManager;
	}	
	
	public synchronized JavaTextTools getJavaTextTools() {
		if (fJavaTextTools == null)
			fJavaTextTools= new JavaTextTools(getPreferenceStore());
		return fJavaTextTools;