You can use the enable method to do so. Enable gives you the liberty of hiding a test case such that it wont be executed. 
Here is an example:-
package testNG;
import org.testng.annotations.Test;
public class Test2 {
  @Test (enabled = true )
  public void g1() 
  {
  System.out.println("test case 1");
  }
  @Test (enabled = true )
  public void g2() 
  {
  System.out.println("test case 2");
  }
  @Test (enabled = false )
  public void g3() 
  {
  System.out.println("test case 3");
  }
  @Test (enabled = true )
  public void g4() 
  {
  System.out.println("test case 4");
  }
}