### Question:
Md5Util { public static String md5(String content) { char[] md5String = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; try { byte[] byteInput = content.getBytes(StandardCharsets.UTF_8); MessageDigest mdInst = MessageDigest.getInstance("MD5"); mdInst.update(byteInput); byte[] md = mdInst.digest(); int j = md.length; char[] str = new char[j*2]; int k = 0; for (byte byte0 : md) { str[k++] = md5String[byte0 >>> 4 & 0xf]; str[k++] = md5String[byte0 & 0xf]; } return new String(str); }catch (Exception e) { logger.warn(e.getMessage(), e); return null; } }  static String md5(String content);  }### Answer:
@Test public void md5() { String md5 = Md5Util.md5("tom--hello"); assertNotNull(md5); }