CODEWITHSUNDEEP
javaobjectinheritancecomparison
user3363135
user3363135

Reputation: 370

java object comparison and inheritance

Need your help with a practice question

how can i modify the below Bar class so that o.equals(0) returns false, you're not allowed to override equals() inherited from the superclass?

 public class Scratchpad {
    public static void main(String[] args) {
        Bar o = new Bar();
        System.out.println(o.equals(o));

    }
}

class Foo {
    public boolean equals(Object o) {
        return this == o;
    }
}

class Bar  extends Foo{

}

Upvotes: 1

Views: 101

Answers (2)

Jeffrey
Jeffrey

Reputation: 44808

Why would you ever need to do this? I suppose you could with something like the following in Foo, but it breaks quite a few good design principles and could cause strange behavior later down the road if anyone else ever needs to use your code.

public final boolean equals(Object o) {
    return o.getClass() == Foo.class && this == o;
}

Note: This also breaks the contract for equals:

It is reflexive: for any non-null reference value x, x.equals(x) should return true.

Upvotes: 1

Alexis C.
Alexis C.

Reputation: 93842

Not sure if this is what you are looking for, but you can overload equals.

class Bar extends Foo{    
    public boolean equals(Bar b){
        return false;
    }
}

Upvotes: 3

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