Click on your project and pick Generate rebel.xml.

You need to generate one rebel.xml file per Eclipse project in your workspace; this includes all Java projects, including Web and EJB projects. Put a rebel.xml in the root of a source folder(*) in each project, and Eclipse will copy the rebel.xml file to the expected target folder when the project builds. For Web projects, JRebel expects to find the rebel.xml configuration file in the WEB-INF/classes directory in the target .war file. For EJB and Java projects, JRebel expects the rebel.xml file to be in the jar root.

The plugin generates the rebel.xml with absolute paths to your workspace. This might be a bad idea as you'd like to share it with other team members. Luckily JRebel will expand expressions like "${myproject.root}" in rebel.xml to a property that you provide. You can set this property as a Java System property (-Dmyproject.root=c:/projects/) or in the JRebel Agent Configuration:

If everyone on your team uses Eclipse and a similar workspace layout, you can even skip using a custom property as every application or server launched with JRebel for Eclipse will have the property rebel.workspace.path set to the Eclipse workspace location and you can use it as “${rebel.workspace.path}” in rebel.xml.