Question

Let’s say I want to override the method equals() of Object:

    public boolean equals(Object o){
      //something
    }

    public boolean equals(SomeClass s){
      //something else
    }

SomeClass is obviously also an Object, so which method will be called if I use equals with an Instance of SomeClass as parameter?

Answer 1

That’s not overriding, it’s overloading. If you do that you’ll end up with two equals methods: one that will be invoked for (subclasees of) SomeClass instances and one for any other objects.

One thing to note is that the method binding will be static: the compiler will decide which one to call based on the declared type of your reference. Therefore, the following will invoke the equals(Object), not equals(SomeClass):

Object o = new SomeClass();
o.equals(o);  // invokes SomeClass.equals(Object)