Given a List of Strings, write a method removeDuplicates that removes duplicate words from the List and returns an ArrayList of all the unique words. The returned ArrayList should be lexically alphabetically.
Think of this problem as a TreeSet 101. TreeSets not only hold only unique values but also maintain the natural order of the elements contained within. Since the output ArrayList needs to be lexically sorted, let us use a TreeSet to maintain the natural sorting order of inserted Strings.