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

If you want to do this statically you can the following.

The examples uses 2 EnumSets in natural-order (==Enum-order) A, B and joins then in an ALL list.

public static final EnumSet CATEGORY_A = EnumSet.of(A_1, A_2);
public static final EnumSet CATEGORY_B = EnumSet.of(B_1, B_2, B_3);

public static final List ALL = 
              Collections.unmodifiableList(
                  new ArrayList(CATEGORY_A.size() + CATEGORY_B.size())
                  {{
                      addAll(CATEGORY_A);
                      addAll(CATEGORY_B);
                  }}
              );