public int compare(Field a, Field b) {
      if (a == b) return 0;
      else if (a == null) return -1;
      else if (b == null) return 1;
      else if (a.equals(b)) return 0;

      int cmp = a.getName().compareTo(b.getName());
      if (cmp != 0) return cmp;

      cmp = a.getDeclaringClass().getName().compareTo(b.getDeclaringClass().getName());
      if (cmp != 0) return cmp;

      return a.getType().getName().compareTo(b.getType().getName());
    }
  /** Calculates a MD5 digest of the class. */
  public String getDigest() {
    try {
      if (_className == null || "".equals(_className)) return "";

      DynamicClassLoader loader =
          (DynamicClassLoader) Thread.currentThread().getContextClassLoader();

      ClassLoader tmpLoader = loader.getNewTempClassLoader();

      Class cl = Class.forName(_className, false, tmpLoader);

      if (cl == null) return "";

      MessageDigest digest = MessageDigest.getInstance("MD5");

      addDigest(digest, cl.getName());

      addDigest(digest, cl.getModifiers());

      Class superClass = cl.getSuperclass();
      if (superClass != null) addDigest(digest, superClass.getName());

      Class[] interfaces = cl.getInterfaces();
      for (int i = 0; i < interfaces.length; i++) addDigest(digest, interfaces[i].getName());

      Field[] fields = cl.getDeclaredFields();

      Arrays.sort(fields, new FieldComparator());

      if (_checkFields) {
        for (Field field : fields) {
          if (Modifier.isPrivate(field.getModifiers()) && !_checkPrivate) continue;
          if (Modifier.isProtected(field.getModifiers()) && !_checkProtected) continue;

          addDigest(digest, field.getName());
          addDigest(digest, field.getModifiers());
          addDigest(digest, field.getType().getName());

          addDigest(digest, field.getAnnotations());
        }
      }

      Method[] methods = cl.getDeclaredMethods();
      Arrays.sort(methods, new MethodComparator());

      for (int i = 0; i < methods.length; i++) {
        Method method = methods[i];

        if (Modifier.isPrivate(method.getModifiers()) && !_checkPrivate) continue;
        if (Modifier.isProtected(method.getModifiers()) && !_checkProtected) continue;
        if (Modifier.isStatic(method.getModifiers()) && !_checkStatic) continue;

        addDigest(digest, method.getName());
        addDigest(digest, method.getModifiers());
        addDigest(digest, method.getName());

        Class[] param = method.getParameterTypes();
        for (int j = 0; j < param.length; j++) addDigest(digest, param[j].getName());

        addDigest(digest, method.getReturnType().getName());

        Class[] exn = method.getExceptionTypes();
        for (int j = 0; j < exn.length; j++) addDigest(digest, exn[j].getName());

        addDigest(digest, method.getAnnotations());
      }

      byte[] digestBytes = new byte[256];

      int len = digest.digest(digestBytes, 0, digestBytes.length);

      return digestToBase64(digestBytes, len);
    } catch (Exception e) {
      log.log(Level.FINER, e.toString(), e);

      return "";
    }
  }