After you have deploy the EAR and accessed the jsp on a url through a browser, I think the application server will check if that jsp file more updated than the compiled classes for your jsp page. If it is more updated, the application server will compile the jsp into Java class again.
Application server will compile your jsp at the first time you
access the jsp until that jsp is updated and redeploy again.
Remove the old EAR from application server and then deploy an updated EAR can ensure there is no cache files of jsp page.