When an object is passed to a method, a copy of the object reference but not the object itself is made : Parameter « Java Source And Data Type « SCJP

1. SCJP
2. Java Source And Data Type
3. Parameter

import java.util.*;

class MainClass {
  public static void main(String args[]) {
    Vector v = new Vector();
    v.add(new String("a"));
    v.add(new String("b"));
    v.add(new String("c"));
    System.out.println(v);
    modifyReference(v);
    System.out.println(v);
    modifyReferencedObject(v);
    System.out.println(v);
  }

  static void modifyReference(Vector v) {
    v = new Vector();
    v.add(new String("1"));
    v.add(new String("2"));
    v.add(new String("3"));
  }

  static void modifyReferencedObject(Vector v) {
    v.removeAllElements();
    v.add(new String("1"));
    v.add(new String("2"));
    v.add(new String("3"));
  }
}