code: @Override
      public User getUser(String username) throws AuthenticationException {
          // Find our user
          String user = file_store.getProperty(username);
          if (user == null) {
              throw new AuthenticationException("User '" + username
                      + "' not found.");
          }
          // Purge any old data and init()
          user_object = new InternalUser();
          user_object.init(username);
          // before returning
          return user_object;
      }
docs: Returns a User object if the implementing class supports user queries
  without authentication.
  
  @param username The username of the user required.
  @return An user object of the requested user.
  @throws AuthenticationException if there was an error retrieving the
  object.