### Question:
CoderUtil { public static String MD5_32bit(String input) { if (input == null || input.length() == 0) { return null; } md.update(input.getBytes()); byte[] digest = md.digest(); String hash = convertToString(digest); return hash; }  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_32bit() { String input = null; assertNull(CoderUtil.MD5_32bit(input)); input = "dubbo"; String output = "AA4E1B8C2CC9DEED96FE012EF2E0752A"; assertEquals(output, CoderUtil.MD5_32bit(input)); }
@Test public void MD5_32bit1() { byte[] input = null; assertNull(CoderUtil.MD5_32bit(input)); input = "dubbo".getBytes(); String output = "AA4E1B8C2CC9DEED96FE012EF2E0752A"; assertEquals(output, CoderUtil.MD5_32bit(input)); }