Description Carsten Hammer 2020-09-02 13:57:58 EDT

Spotbugs error LI_LAZY_INIT_UPDATE_STATIC 

Bug: Incorrect lazy initialization and update of static field org.eclipse.ltk.internal.core.refactoring.RefactoringCorePlugin.fRefactoringUndoContext in org.eclipse.ltk.internal.core.refactoring.RefactoringCorePlugin.getUndoContext()

This method contains an unsynchronized lazy initialization of a static field. After the field is set, the object stored into that location is further updated or accessed. The setting of the field is visible to other threads as soon as it is set. If the further accesses in the method that set the field serve to initialize the object, then you have a very serious multithreading bug, unless something else prevents any other thread from accessing the stored object until it is fully initialized. 

Even if you feel confident that the method is never called by multiple threads, it might be better to not set the static field until the value you are setting it to is fully populated/initialized. 

	public static IUndoContext getUndoContext() {
		if (fRefactoringUndoContext == null) {
			fRefactoringUndoContext= new RefactoringUndoContext();
			IUndoContext workspaceContext= ResourcesPlugin.getWorkspace().getAdapter(IUndoContext.class);
			if (workspaceContext instanceof ObjectUndoContext) {
				((ObjectUndoContext)workspaceContext).addMatch(fRefactoringUndoContext);
			}
			IOperationHistory operationHistory= OperationHistoryFactory.getOperationHistory();
			operationHistory.setLimit(fRefactoringUndoContext, 5);
		}
		return fRefactoringUndoContext;
	}