private static final byte[] hash(final byte[] value) throws NoSuchAlgorithmException {
  MessageDigest md=MessageDigest.getInstance("MD5");
  md.reset();
  md.update(value);
  return md.digest();
}

private static final byte [ ] hash ( final byte [ ] value ) throws NoSuchAlgorithmException { MessageDigest md = MessageDigest . getInstance ( "MD5" ) ; md . reset ( ) ; md . update ( value ) ; return md . digest ( ) ; }
return the hash of an array of bytes . this method is thread safe .
