Use of “this” keyword in java [duplicate]

this is an alias or a name for the current instance inside the instance. It is useful for disambiguating instance variables from locals (including parameters), but it can be used by itself to simply refer to member variables and methods, invoke other constructor overloads, or simply to refer to the instance. Some examples of applicable uses (not exhaustive):

class Foo
{
     private int bar; 

     public Foo() {
          this(42); // invoke parameterized constructor
     }

     public Foo(int bar) {
         this.bar = bar; // disambiguate 
     }

     public void frob() {
          this.baz(); // used "just because"
     }

     private void baz() {
          System.out.println("whatever");
     }

}