code: public static String normalize(CharSequence src, Form form) {
        switch (form) {
          case NFD: return normalizeNFD(src.toString());
          case NFC: return normalizeNFC(src.toString());
          case NFKD: return normalizeNFKD(src.toString());
          case NFKC: return normalizeNFKC(src.toString());
          default:
            throw new AssertionError("unknown Form: " + form);
        }
      }
docs: Normalize the character sequence <code>src</code> according to the
  normalization method <code>form</code>.
  
  @param src character sequence to read for normalization
  @param form normalization form
  @return string normalized according to <code>form</code>