问题
What happens when a method in super class is synchronized, but you override the method in a subclass and don't synchronize it ?
回答1:
If a method in super class is synchronized, but you override the method in a subclass and don't synchronize it, then the method is no longer synchronized if called on the subclass.
来源：https://stackoverflow.com/questions/10173345/overriding-a-synchronized-method