How do I join two lists in Java?

Question

Conditions: do not modifiy the original lists; JDK only, no external libraries. Bonus points for a one-liner or a JDK 1.3 version.

Is there a simpler way than:

Answer 1

public static  List merge(@Nonnull final List... list) {
    // calculate length first
    int mergedLength = 0;
    for (List ts : list) {
      mergedLength += ts.size();
    }

    final List mergedList = new ArrayList<>(mergedLength);

    for (List ts : list) {
      mergedList.addAll(ts);
    }

    return mergedList;
  }