class Hexadecimals {

  protected static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();

  public static String byteToHexString(byte b) {<FILL_FUNCTION_BODY>}

  public static String toHexString(byte... bytes) {
    StringBuilder stringBuilder = new StringBuilder();
    for (byte b : bytes)
      stringBuilder.append(byteToHexString(b));

    return stringBuilder.toString();
  }

  private Hexadecimals() {}
}

    int v = b & 0xFF;
    return new String(new char[] { HEX_ARRAY[v >>> 4], HEX_ARRAY[v & 0x0F] });
  
<no_super_class>