Horizontal scalaibility in a Spring based messaging application.

Question

Hi Techies,

I work on Spring based messaging application. We are undergoing a scalable tests for our product. However the application is not scalable horizontally after a certain limit. We are finding out the code points to be modified but would like to get an expert comment/pointers in order to make changes in the application.

Can there be any configurations to speed up the responsiveness of application?

Thanks for valuable inputs.

~a