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

This is simple and just one line, but will add the contents of listTwo to listOne. Do you really need to put the contents in a third list?

Collections.addAll(listOne, listTwo.toArray());