Adding a method to an interface is equivalent to adding an abstract method to a base class; any class that implements the interface will break because the class does not implement the new method.
Adding a method to an interface is equivalent to adding an abstract method to a base class; any class that implements the interface will break because the class does not implement the new method.
对于一个类来说添加接口和添加抽象类是一样的；执行接口的时候类会中断，因为类不能执行新的方法。