public  class ListMerge
{
   public static void main( String[] args) 
   {

      Scanner input = new Scanner(System.in);

      System.out.println ("Input length of arraylist 1:");
      int n = input.nextInt();
      ArrayList x = new ArrayList();
      ArrayList y = new ArrayList();
      for (int i = 0; i < n; i++)
      {
        System.out.println ("Input x[ " + i +"] :" );
         x.add(new Integer(i));

      }


      System.out.println ("Input length of arraylist 2:");
      int m = input.nextInt();


      for (int i = 0; i < m; i++)
      {
        System.out.println ("Input y[ " + i +"] :" );
        y.add(new Integer(i));

      }
      List<Integer> all = new ArrayList<Integer>();

      all.addAll(x);
      all.addAll(y);
      System.out.println(all);


  }
}

I did this but its not taking values from user. pls tell me why....