Current application:
I have one spring web application running on app server A ( on DB -myDatabase) where -
user can fill/submit a form,check accounts,print reports.
Main landing page has link from where user can start filling a form and after submitting,it comes back to
landing page. Application works fine. And i need to make some additions.

We are thinking of creating a small app (has to be server B) which in future would contain web service client code.

Requirement:
When user submits the form and is going back to landing page,i also want this action to call my other app on server B simulaneously. And main app on server A should resume its operation normally.

(Note:App on server B is not written yet so could be plain java or web app)

I want some suggestions on implementations.

I am looking into different alternatives and technologies existing but couldnot think much.

1.scheduler based service: Writing some flag into db table when form is submitting and making other java app reading database after some intervals.
But we also dont want App on server B to access our dB (myDatabase) directly.

2.My app on server A is spring based app (M-V-C model).
Before returning back to landing page, i can call a popup page, with hard-coded URL to app on serverB
But i am not sure how reliable this is..

Any other suggestions.