Play recompiles files for you automatically after changes have been made and the browser refreshed. This makes Jrebel unnecessary for Play.
Our flagship product JRebel lets you change your application code and just hit refresh in your browser and you’ll see the changes instantly. Play! framework offers something similar. I have not read enough source code but it seems that with custom extra metadata (see your app’s tmp/bytecode/DEV), a stateless model and the custom runner (play run) they will give you the power of changing code on the fly. If they don’t support the change they will restart your app automatically for you.
http://zeroturnaround.com/rebellabs/my-top-5-play-framework-features/
However, if you include a library in the Play project that you are making chages to then Jrebel can come in handy so those changes are auto-compiled.
Should Jrebel be included in the Play project or in the library? What would be the simplest workflow?