Ravi C.

Using the this Keyword Within an instance method or a constructor, this is a reference to the current object — the object whose method or constructor is being called. You can refer to any member of the current object from within an instance method or a constructor by using this. Using this with a Field --------------------------------- The most common reason for using the this keyword is because a field is shadowed by a method or constructor parameter. For example, the Point class was written like this public class a { public int x = 0; public int y = 0; //constructor public a(int a, int b) { x = a; y = b; } } but it could have been written like this: public class a { public int x = 0; public int y = 0; //constructor public a(int x, int y) { this.x = x; this.y = y; } } Each argument to the constructor shadows one of the object's fields — inside the constructor x is a local copy of the constructor's first argument. To refer to the class a's field x, the constructor must use this.x. Using this with a Constructor From within a constructor, you can also use the this keyword to call another constructor in the same class. Doing so is called an explicit constructor invocation. for example: public class b { private int x, y; private int width, height; public b() { this(0, 0, 1, 1); } public b(int width, int height) { this(0, 0, width, height); } public b(int x, int y, int width, int height) { this.x = x; this.y = y; this.width = width; this.height = height; } ... }