code: public boolean endsWith(CharSequence suffix) {
          int suffixLen = suffix.length();
          return regionMatches(length() - suffixLen, suffix, 0, suffixLen);
      }
docs: Compares the specified string to this string to determine if the specified string is a suffix.
  
  @param suffix the suffix to look for.
  @return {@code true} if the specified string is a suffix of this string, {@code false} otherwise.
  @throws NullPointerException if {@code suffix} is {@code null}.