Using JRebel for Backend applications

[Zico Gupta]

Hello Anton,
I'm involved in developing back end application using J2EE. The developement work is done on windows machine and run on Websphere Application server installed in a different machine which runs on linux.

Whenever a class is modified, I need to upgrade the corresponding jar file with the changed class, copy the same to the specific ear and then either restart the websphere or the ear from IBM administrative console. My question is, whether using Jrebel allow me to eliminate some of these activities?

Thanks & Regards,
Zico

[Anton Arhipov]

Hello,

Yes, JRebel can help you quite a lot here, although you'd need to do some work to adjust your environment. The thing is that JRebel doesn't work with remote servers as it is running in the server it self - it is a javaagent.

We have some users who reported the following setup. The application server is running on a remote Linux machine and the developer works at his Windows workstation. Then they set up a shared network storage that could be accessible both from the Linux server as well as from Windows machine. JRebel has to be able to access the classes/resources that are mapped from your IDE. So if the IDE is configured to put the required resources to the network storage, then JRebel agent can be configured to seek for the resources in the same location also. This is done using rebel.xml configuration file which includes the paths to the location where the compiled classes are.

So this way you can save time for packaging the artifact, copying it to the server, redeploying, loosing state of the application, navigating through several screens to see if the change is applied, restarting the server once you hit OutOfMemoryError.

I think your case is a perfect example of the environment which JRebel tries to fix.