I've been checking out JRebel. According to their site:
"JRebel is an anything-Java plugin that speeds up JVM-based development (Java, Scala, Groovy) by reloading changes made in your workspace into a running JVM, without restarts or redeploys, maintaining the state of the application while you’re coding."
This seems to be the same as what we're already achieving with Eclipse, Netbeans and IntelliJ: we save and our changes are deployed instantly. What additional benefit(s) would JRebel give us?
Could someone explain it to me?
The IDE (Eclipse, NetBeans or IntelliJ) automatically redeploy the application if configured so, which is not instant. Basically, it is just the automation that still results in real redeployment of the application, including creating of a new classloader and all the complementary stuff that is involved into initialization process.
In some cases, IDE in combination with some containers can preserve the session state - if that works for you that's awesome. If not - here you go - JRebel is the answer.
In case of packaged deployment the build phase adds up, but by using JRebel you just eliminate that all at once.