public static List addAll(List dest, List src, boolean allow_duplicates) { for (Iterator e = src.iterator(); e.hasNext();) { Object o = e.next(); if (!allow_duplicates && !dest.contains(o)) dest.add(o); } return dest;
public static List addAll(List dest, List src) { return addAll(dest, src, true);
  public static List addAll(List dest, List src, boolean allow_duplicates) {    for (Iterator e = src.iterator(); e.hasNext();) {      Object o = e.next();      if (!allow_duplicates && !dest.contains(o))        dest.add(o);    }    return dest;  }