When should I use “this” in a class?

Question

I know that this refers to a current object. But I do not know when I really need to use it. For example, will be there any difference if I use x i

Answer 1

"this" is also useful when calling one constructor from another:

public class MyClass {
    public MyClass(String foo) {
        this(foo, null);
    }
    public MyClass(String foo, String bar) {
        ...
    }
}