Usage of this keyword in salesforce

This keyword used to represent the current instance of the class.

Example:

1. public class ThisKeyWordExample
2. {
3.     String str  = 'Test Me';
4.    
5.     public void strMethod(String str)
6.     {
7.         System.debug('--Parameter Value--'+str);
8.         System.debug('--Current Instance Value--'+this.str);
9.     }
10.    
11. }

The above example has One Instance Variable & One Local Variable or Method parameter with same name(i.e. str).

str = Refers parameter value.

this.str = Refers the current instance variable value.

To execute this class go to Developer Console, paste the below line then click execute.

1. ThisKeyWordExample thisExample = new ThisKeyWordExample();
2. thisExample.strMethod('Test You');

Reference: this keyword