I had a doubt that will a re-start of of our application which has TOMCAT as the web server and JBOSS as the Application server is required if there is a change in server time? Our Server OS is RHEL 4.0(Linux). The server time is probably behind the time by 15 mins.
2) Doing it in a non-production environment will not be feasible as that would not be a real test for this and there are problems in putting up our test environment.
Why would it be "not a real test"? Infact, you don't even need your application to be deployed on the test setup. All you need is a test application (with just a few lines of code) which gets the current system time and prints it. And you can see if the output changes on changing the system time.
I had a doubt that will a re-start of of our application which has TOMCAT as the web server and JBOSS as the Application server is required if there is a change in server time?
Do you have the option of restarting the server? If yes, then i would strongly recommend doing that in production - because any system level changes usually lead to some issue here and there (maybe not in your application but in some other application).
If we consider development environment there is no need of re-starting the server(web as well as application). changing the server time will immediately reflected. But considering a production environment and running application it is always better to restart the server as Jaikiran Pai said.otherwise it may leads to malformed response generation for the request by the server.