import  java.security.*;
...

 private   boolean  checkMD5(String password, String md5hash) {
   try  {
    MessageDigest md = MessageDigest.getInstance("MD5");
    md.update(password.getBytes());
     byte [] array = md.digest();

    StringBuffer sb =  new  StringBuffer();
     for  ( int  i =  0 , n = array.length; i < n; i++) {
       int  b = array[i] & 0xFF;
       if  (b < 0x10)
        sb.append('0');
      sb.append(Integer.toHexString(b));
    }
     return  sb.toString().equals(md5hash);
  }  catch  (NoSuchAlgorithmException e) {
     return  false;
  }
}