一道我的考研题
Using the example of "Payroll System Using Polymorphism " to create the example of Animal, Dog, and Cat by using Polymorphism, and to use one loop to make the cat and dog "Jiao " one time!

[解决办法]
多态嘛，animal是父类，有一个方法jiao()，cat dog继承animal，然后循环调用父类的jiao()
[解决办法]
java中没有多重继承，只有接口可以变相的实现，
public interfece Animal{}
public class dog extends Animal{}
public class cat extend Animal{}