public static Charset forName(String charsetName) {
    if (charsetName.startsWith(NAME_PREFIX)) {
      Native2AsciiCharset cached = cache.get(charsetName);
      if (cached == null) {
        cached = new Native2AsciiCharset(charsetName);
        Native2AsciiCharset prev = cache.putIfAbsent(charsetName, cached);
        if (prev != null) cached = prev;
      }
      return cached;
    }
    return null;
  }
public static Charset forName(String charsetName)