Question

Assume that there is a class like the following.

public Class SomeClass {
    private A getA() {
        ...
    }

    public void show() {
        A a = getA();    // CASE #1
        ...
    }

    public void show2() {
        A a = this.getA();    // CASE #2
        ...
    }

Their result are same, isn’t? My idiot co-worker insisted that’s right!!(it means they’re different.)

Answer 1

They’re the same in this context. I’d advocate not using this since it’s implied and it’s just cluttering up the code by being there, but it makes no practical difference whether it’s there or not.

It’s not useless though. The this keyword is required sometimes, for instance:

• When a local variable / parameter hides a field it’s used to differentiate between them
• When referring to the outer instance of a class from the inner instance (use Outer.this)
• When using explicit generic types to call a method rather than just infered types (you can’t just do <String, String>stringMethod(), it has to be this.<String, String>stringMethod().

That’s by no means an exhaustive list, just serves as an example to demonstrate while it doesn’t make a difference in this case, it can do in other cases!