I have started to use JRebel and believe me, that's a great tool! To configure it, you have to specify the absolute path of your project directories in the configuration file. When working in a team, it is always problematic to have a configuration file with absolute path in version control.

A plugin for maven exists to generate the rebel.xml files but for  gradle, nope. Sadly it seems that Zeroturnaround has removed their gradle plugin from their repository.

Hopefully generating a xml file in groovy is a piece of cake. So I have done my own code to generate the rebel.xml file before building the war file.

task generateRebel << {
    def rebelFile = sourceSets.main.output.classesDir.absolutePath + '/rebel.xml'

    def srcWebApp = project.webAppDir.absolutePath
    def writer = new FileWriter(rebelFile)
    new MarkupBuilder(writer).application() {
        classpath{
            dir( name:sourceSets.main.output.classesDir.absolutePath )
        }
        web{
            link(target:'/'){
                dir(name:srcWebApp)
            }
        }
    }
}
war.dependsOn generateRebel

That's it! Your rebel.xml will be generated on the fly, you just need to activate JRebel on the server!