Looking at the FilteredList class in JavaDoc, one constructor takes Matcher<? super E> matcher , and the other Matcher<E> matcher. Seems like they should both be "Matcher<E> matcher".

FilteredList(java.util.List<E> source, Matcher<? super E> matcher, FilterableList.FilterMode mode)
          Constructs a new FilteredList wrapper around the source list.
FilteredList(java.util.List<E> source, Matcher<E> matcher)
          Constructs a new FilteredList wrapper around the source list using the FilterableList.FilterMode.BATCH mode.