ObjReferenceTest

public class ObjReferenceTest {

  private int age = 12;

  public static void main(String[] args) {
		
    ObjReferenceTest obj = new ObjReferenceTest();
    System.out.println("[initially]");
    System.out.println("Age = " + obj.age + " , hashcode = " + System.identityHashCode(obj) + "\n");
		
    obj.changeAge99(obj);
    System.out.println("Age = " + obj.age + " , hashcode = " + System.identityHashCode(obj)  + "\n");
		
    obj.changeAge88(obj.age);
    System.out.println("Age = " + obj.age + ", hashcode = " + System.identityHashCode(obj.age));
  }
	
  private void changeAge99(PrimitiveAsParameter obj) {
    System.out.println("[changeAge99] Parameter's hashcode = " + obj.hashCode());
    obj.age = 99;
  }
	
  private void changeAge88(int age) {
    System.out.println("[changeAge88] age hashcode = " + System.identityHashCode(age));
    age = 88;
  }
}