Dog dog=new Dog();

System.out.println(dog instanceof Dog);          //打印true

System.out.println(dog instanceof Animal);       //打印true

System.out.println(dog instanceof Creature);         //打印true

System.out.println(dog instanceof Object);        //打印true

//instanceof 右边的操作元也可以是接口名

interface interfaceEx();

class A implements InterfaceEx();

class B extends A();

//对于以下代码，打印true

B b=new B();

System.out.printIn(b instanceof InterfaceEx);  打印true