Question about Spring RMI calls

Hi experts in Spring Framework.

I am a novice and I am hoping you can shed some light on this issue for me.

My question is "Is a spring RMI call synchronous?" If it is, can it be made to asynchronous?

I am currently working on a project where in the server side GUI sends a message and the client side should take that message and display it in a JFrame or JDialog. However, I notice if I made the Frame or Dialog modal, it holds the execution thread on the server side Gui.

I am using the version 1.2.6

Thank you very much