Java - adding elements to list while iterating over it

Question

I want to avoid getting ConcurrentModificationException. How would I do it?

Answer 1

You want to use a ListIterator. You can get one of these from any kind of list, though for efficiency you probably want to get one from a LinkedList.

import java.util.*;
class TestListIterator {
  public static void main(String[]args) {
    List L = new LinkedList();
    L.add(0);
    L.add(1);
    L.add(2);
    for (ListIterator i = L.listIterator(); i.hasNext(); ) {
      int x = i.next();
      i.add(x + 10);
    }
    System.out.println(L);
  }
}

Prints [0, 10, 1, 11, 2, 12].