equals方法重写

public class Demo{
    public static void main(String[] args){
        Animal a1 = new Tiger();
        Animal a2 = new Fish();
        Animal a3 = new Tiger();
        a1.name = "aaa";
        a1.age = 12;
        a1.type ="tiger";
        
        a2.name = "aaa";
        a2.age = 12;
        a2.type ="tiger";
        
        a3.name = "aaa";
        a3.age = 5;
        a3.type ="tiger";
        
        System.out.println(a1.equals(a2));
        System.out.println(a3.equals(a2));
        
        
    }
}

class Animal{
    String name;
    int age;
    String type;
    
    public boolean equals(Object obj){
        boolean bool = false;
        if(this == obj){bool = true;}
        if(obj == null){bool = false;}
        if(obj instanceof Animal){
            bool = ((Animal)obj).name==this.name
                &&((Animal)obj).age==this.age
                &&((Animal)obj).type==this.type;
        }
        return bool;
    }
}

class Tiger extends Animal{}

class Fish extends Animal{}