Java 集合 复制Vector所有元素

import java.util.Collections;
import java.util.Vector;
public class VectorCopyExample {
  public static void main(String args[])
  { 
       //First Vector of String type
       Vector<String> va = new Vector<String>();
       //Adding elements to the first Vector
       va.add("AB");
       va.add("BC");
       va.add("CD");
       va.add("DE");

       //Second Vector
       Vector<String> vb = new Vector<String>();
       //Adding elements to the second Vector
       vb.add("1st");
       vb.add("2nd");
       vb.add("3rd");
       vb.add("4th");
       vb.add("5th");
       vb.add("6th");

       /*Displaying the elements of second vector before
         performing the copy operation*/
       System.out.println("Vector vb before copy: "+vb);

       //Copying all the elements of Vector va to Vector vb
       Collections.copy(vb, va);

       //Displaying elements after copy
       System.out.println("Vector vb after copy: "+vb);
   }
}

Vector vb before copy: [1st, 2nd, 3rd, 4th, 5th, 6th]
Vector vb after copy: [AB, BC, CD, DE, 5th, 6th]