### Question:
CoderUtil { public static String MD5_16bit(String input) { String hash = MD5_32bit(input); if (hash == null) { return null; } return hash.substring(8, 24); }  static String MD5_16bit(String input); static String MD5_32bit(String input); static String MD5_32bit(byte[] input); static String decodeBase64(String source);  }### Answer:
@Test public void MD5_16bit() { assertNull(CoderUtil.MD5_16bit(null)); String input = "dubbo"; String output = "2CC9DEED96FE012E"; assertEquals(output, CoderUtil.MD5_16bit(input)); }