javaµÚ5ÌìµÄ´úÂë

/*****************Animal.java begin ***********************/
 public class Animal{
 
 public void jj(){
  
 }
 
 public static void main(String args[]){
  //±àÒëʱÀàÐÍ       //ÔËÐÐʱÀàÐÍ
  Animal animal=new Dog();//animal¶ÔÏó±»ÉùÃ÷ΪAnimalÀàÐÍ£¬ÒýÓÃDog¶ÔÏó
  Dog dog=(Dog) new Animal();
  Animal animal1=new Cat();
  System.out.println(animal instanceof Animal );//true
  System.out.println(animal instanceof Dog );//true
  System.out.println(animal instanceof Cat );//false
  
  Animal animal2=new Cat();//animal¶ÔÏó±»ÉùÃ÷ΪAnimalÀàÐÍ£¬ÒýÓÃcat¶ÔÏó
  System.out.println(animal1 instanceof Animal );
  System.out.println(animal1 instanceof Dog );
  System.out.println(animal1 instanceof Cat );
  
//  Dog dog=new Dog();
  System.out.println(dog instanceof Dog );//true
  System.out.println(dog instanceof Animal );//true
  System.out.println(dog instanceof Object );//true
  
  //DogÀàÓëCatÀàÖ®¼äûÓÐÖ±½Ó»ò¼ä½ÓµØ¼Ì³Ð¹Øϵ
//  System.out.println(Dog instanceof Cat);
 }
}
class Dog extends Animal{
 String name;
 public void jj(String name){
  
 }
 
}
class Cat extends Animal{
 
}
/*****************Animal.java end ***********************/
/*****************TestDuoTai.java begin ***********************/
public class TestDuoTai{
 
 public static void main(String args[]){
  //ÒýÓõÄÊÇCat1¶ÔÏó(µ÷ÓÃÓз½·¨¸²¸ÇµÄ·½·¨)
  Animal1 a=new Cat1();
  a.show();
  a.eat();
//  a.a();
  
 }
}
class Animal1{
 public void a( ){}
 
 public void eat(){
  System.out.println("Animal1 eat...");
 }
 
 public void show(){