apache/commons-lang — pull request #13 by patrick-a-cavanaugh (2014-01-14 20:07:42+00:00)
Title: Update ImmutablePair to be not final

The sibling class MutablePair is not final, and the JavaDoc for ImmutablePair also states it is not final: "The class is also not {@code final}, so a subclass could add undesirable behaviour".