JRebel (formerly JavaRebel) is a small application that allows you to see changes you make to your code without redeploying it by mapping your project workspace directly to a running application. So, when you make a change to any class or resource in your IDE the change is immediately reflected in the application, skipping build and redeploy phases.
They’ve posted a survey (700+ respondents) that says the redeploy & restart phase wastes 2-8 weeks of your development time annually, depending on the container you use.
The plugin itself lets you configure JRebel for projects and containers directly within IntelliJ IDEA, using a neat GUI, instead of going to the command line. Basically, if you’re interested in JRebel, then it’s easier than ever to work with it directly from IntelliJ IDEA.
If you’re interested in writing your own plugins for IntelliJ IDEA, check out our repository of 550+ extensions, and information on how you can get started, here: http://plugins.intellij.net/