code: private static <L extends List<String>> L trimStringList(L strings)
      {
          for (ListIterator<String> listIt = strings.listIterator(); listIt.hasNext(); )
          {
              String string = listIt.next().trim();
              listIt.set(string);
          }
          return strings;
      }
docs: Applies {@link String#trim()} to each String in the {@link List}
  
  @return the input list, mutated in place, containing trimmed strings.