Is a hot reset possible in Glassfish, at least for development purposes?

I have had this question since I learned about Erlang and its ability to hot-swap individual modules and even functions on a production server.

We are developing a project in Java for Glassfish 2.1. This is basically a .ear file, consisting of a bunch of .war modules.

So, every time, I make small changes in the code of one of the modules, in order to check this change, I have to redistribute the whole ear on my development server. Does this really work?

Basically, we have several replacement levels - are they possible?

• Military module. It happens during a large number of commits from several developers. Is it possible to replace this module on a production server without redeploying the entire ear file.
• Java classes (action descriptors, etc.). Is it possible to simply replace the bytecode of classes that have been changed?
• Jsp pages I think they are run by an independent special jsp interpreter in a glass shawl. Thus, it should definitely be able to hot reload one modified page.
• I know that I can completely replace various parts of the HTML design, such as css or js files, or image files. But what about the bytecode files described above?