Out of curiosity, what does this deployer do? I read the "Behind the scenes" section but couldn't completely grasp it.
intended to skip long lasting Deployments/Re-Deployments
Does this mean the tool is used for picking up changes to class files without redeploying the application? Or is it something else?
partially yes. There are commercial tools like JRebel which achieve the same using different approaches.
Have you ever developed a Web-App consisting of more than one IDE (Eclipse) Projects? Eclipse uses a classes-Directory for each Project, so you always need to copy all classes to WEB-INF or create Jars after you changed the code. This sucks if you have one Web-App and the code for the App is split into multiple Eclipse Projects.
Because of this I wrote that deployer. Basically with Development Deployer you can tell JBoss to use additional classes-Directories, which can be outside the WEB-INF Directory.
Developers, that have just one Eclipse Project for their Web-App don't need this Deployer as you can point JBoss out of the box to an external deployment location.
Hoping, that I could answer your Questions.
Thanks, I understand it better now
Are you going to support multy-module project with complicated Maven/And build scripts?
Basically....yes. By now, I started with Web-Projects (WAR Packaging). I've full EAR (SAR/HAR) support on my Roadmap.
Maven for example has a very defined compiler output. When you build once your Project with Maven, all necessary prequisites are fulfilled in this moment - that's the moment where you would start also your JBoss AS to debug your app. JBoss can be told by Development Deployer Config to use "target/classes" of your dependent Projects (not the Maven built JAR's) to receive incremental changes you make to your code while debugging.
Complex Ant Scripts should work too, but there are sure some scenarions, where it could not work out.
Since Java VM supports Hot Swapping, classes which were loaded once, are automatically updated thru the debugger connection (when you change them in Eclipse). Classes, which were not loaded by the VM, but modified in Eclipse are also updated, because JBoss Development Deployer includes the Class-Path where classes are compiled to.