Adding Multiple Values in ArrayList at a single index

Question

I have a double ArrayList in java like this.

List values = new ArrayList(2);

Now what I want t

Answer 1

import java.util.*;
public class HelloWorld{

 public static void main(String []args){
  List threadSafeList = new ArrayList();
    threadSafeList.add("A");
    threadSafeList.add("D");
    threadSafeList.add("F");

Set threadSafeList1 = new TreeSet();
    threadSafeList1.add("B");
    threadSafeList1.add("C");
    threadSafeList1.add("E");
    threadSafeList1.addAll(threadSafeList);


 List mainList = new ArrayList();   
 mainList.addAll(Arrays.asList(threadSafeList1));
 Iterator mainList1 = mainList.iterator();
 while(mainList1.hasNext()){
 System.out.printf("total : %s %n", mainList1.next());
 }
}
}