code: private void doLogin(LoginGenerator.LoginRecord login) {
          // Synchronously call the "Login" procedure passing in a json string containing
          // login-specific structure/data.
          try {
              ClientResponse response = client.callProcedure("Login",
                                                              login.username,
                                                              login.password,
                                                              login.json);
  
  
              long resultCode = response.getResults()[0].asScalarLong();
              if (resultCode == LOGIN_SUCCESSFUL)
                  acceptedLogins.incrementAndGet();
              else
                  badLogins.incrementAndGet();
          }
          catch (Exception e) {
              badLogins.incrementAndGet();
              e.printStackTrace();
          }
      }
docs: Invoke the Login stored procedure to add a login record to the database.
  If the login is called multiple times for the same username, the last accessed
  time for the login is updated.  Thus this sample client can be run repeatedly without
  having to cycle the database.