/** Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  http://www.corewebprogramming.com/.
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.
 */

import java.awt.Point;

public class ReferenceTest {
  public static void main(String[] args) {
    Point p1 = new Point(1, 2); // Assign Point to p1
    Point p2 = p1; // p2 is new reference to *same* Point
    print("p1", p1); // (1, 2)
    print("p2", p2); // (1, 2)
    triple(p2); // Doesn’t change p2
    print("p2", p2); // (1, 2)
    p2 = triple(p2); // Have p2 point to *new* Point
    print("p2", p2); // (3, 6)
    print("p1", p1); // p1 unchanged: (1, 2)
  }

  public static Point triple(Point p) {
    p = new Point(p.x * 3, p.y * 3); // Redirect p
    return(p);
  }

  public static void print(String name, Point p) {
    System.out.println("Point " + name + "= (" +
                       p.x + ", " + p.y + ").");
  }
}