Java and rest OOP languages - when to use super or this keywords

Question

I have been programming java for like a year or more, and i have always used the this and super keywords.

And yesterday my mate read one source of mine, and told me not to over use it unless you are overriding the method.

class A extends JPanel {
     public A {
         super.setSize(400, 400);// instead of not using super keyword
     }
}

But what he meant on how to use it, is this:

class A extends JPanel {
    public A {
        super.setSize(4,4);
    }

    public void setSize(int a, int b) {}
}

So the language will know that your constructor calls the parent method and not local.

Should i only use the the keywords in this situation only or use the keywords everywhere for better readibly?

I know that this keyword is returning the whole local instance including the parent and all of its parents and interfaces.

And the super keyword returns the instance of the parent class and all of its instances (parents and interfaces).

But my question is, should you always use these keywords?

Answer 1

You need to be aware of all the special cases where it is compulsory to use super or this. You described one of those corner cases - overridden functions. You will learn more special cases as you go on.

Other than those specific cases, using this and super is a matter of preference. They produce the same machine code, and so they are exactly the same as far as the machine is concerned. However, they differ in terms of their readability to a person.

It is important to pick one style and use it consistently. By this, I mean not just you, but your entire team. Everyone decides on one way of doing things and sticks to it. This makes it easy to understand the team's code. This is called a "coding standard".

Check if there are any published coding guidelines or coding standards set by the company or the team. If yes, just follow them. Otherwise, see what the rest of the team normally uses. You may want to discuss this with your team to officially decide on a standard.