Name: vi73552 Date: 04/11/99


Compile the following:

import java.awt.*;
import java.util.*;

public class test
{
   class testclass
   {
      String st1;
      String st2;
   }
   Vector master_v1, v1;
   public test()
   {
     master_v1 = new Vector();
     v1 = new Vector();
     testclass tc1 = new testclass();
     testclass tc2 = new testclass();
     testclass tc3 = new testclass();
     tc1.st1 = "tc1st1";
     tc1.st2 = "tc1st2";
     tc2.st1 = "tc2st1";
     tc2.st2 = "tc2st2";
     tc3.st1 = "tc3st1";
     tc3.st2 = "tc3st2";

     master_v1.addElement((Object)tc1);
     master_v1.addElement((Object)tc2);
     master_v1.addElement((Object)tc3);
   }
   public void exec()
   {
     for (int z = 0; z < 2; z++)
     {
       v1 = (Vector)master_v1.clone();
       for(int i=0; i < v1.size();i++)
       {
          System.out.println("master tc:"+i);
          System.out.println("st1:"+i+" = "+((testclass)v1.elementAt(i)).st1);
          System.out.println("st2:"+i+" = "+((testclass)v1.elementAt(i)).st2);
       }
       testclass temp = (testclass)v1.remove(1);
       temp.st2 = "this is new!!";
       v1.addElement((Object)temp);
       for(int i=0; i < v1.size();i++)
       {
          System.out.println("tc:"+i);
          System.out.println("st1:"+i+" = "+((testclass)v1.elementAt(i)).st1);
          System.out.println("st2:"+i+" = "+((testclass)v1.elementAt(i)).st2);
       }
     }
     v1.clear();
   }
   public static void main(String argv[])
   {
      test t1 = new test();
      t1.exec();
   }
}

Notice in the output that the second time thru for "master tc:tc2.st2" output
won't be "tc2st2", but "this is new!!". Per the JDK API docs for Vector.clone():

Returns a clone of this vector. The copy will contain a reference to a clone of the internal data
array, not a reference to the original internal data array of this Vector object.

This is not happening, instead, this acts more like ArrayList.clone() which states:
Returns a shallow copy of this ArrayList instance. (The elements themselves are not copied.)

I'm trying to use vectors as a substitute for dynamically linked lists but if I can't
clone them off a master vector list, its a pretty useless class.
(Review ID: 56549)
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