code: public static @Nullable String trim(@Nullable String s) {
  		return (s != null ? s.trim() : s);
  	}
docs: Makes sure a {@linkplain String} is either {@code null} or trimmed.
  
  @param s the {@linkplain String} to trim.
  @return the submitted {@linkplain String} in trimmed form or {@code null} if {@code null} was submitted.