What does "this" do?

[BenH]

Hi there!

I am studying the keyword "this". What exactly does it do? I am confused.

[Fubarable]

It references the current object.

For more, please have a look here: Using the this keyword.

[Eranga]

In other word this keyword is useful when you need to refer an instance of a class from its method. So you can use it to avoid name conflict with instance and local variables. Go through the sample code with the comments below.

public class ThisKeywordDemo {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Multiplication obj = new Multiplication(12, 12);
		System.out.println("Multiplication is: " + obj.MultiValue());
	}

}

class Multiplication {
	// Declare two instance variables
	int iNum1;
	int iNum2;
	
	// Constructor with two local variables with the same names 
	// as instance variables of the class
	public Multiplication(int iNum1, int iNum2) {
		// So here we are going to initialize instance variables to the same value
		// as local variables in the constructor. But how?
		
		this.iNum1 = iNum1;
		this.iNum2 = iNum2;
		
		// Once you run the code and see the result, change the instance variable
		// names into different and assign the value from the local variables without
		// using the 'this' keyord. Compile the code ans run.
	}
	
	public int MultiValue() {
		// Here I haven't use 'this' keyword. Why?
		return (iNum1 * iNum2);
	}
}