1 import java.util.*; 2 class Animalb{ 3     String name; 4     void eat(){ 5         System.out.println("动物在吃东西啦"); 6     } 7 } 8 class Doga extends Animalb{} 9 class Cata extends Animalb{}10 11 public class FourFei {12    public static void main(String[] args){13        Doga a = new Doga();14        Cata c = new Cata();15        16        ArrayList<Object> list = new ArrayList<Object>();17        list.add(a);18        list.add(c);19        20        if(a.equals(c)){ //判断两个对象是否相等21            System.out.println("true");22        }else{23            System.out.println("false");24        }25        System.out.println(c.equals(a));26        System.out.println(c.getClass());27        System.out.println(c.hashCode());28        System.out.println(c.toString());29        30    }31 }