Trying to search for a good Java game Engine

Well, there is jME3. Fairly modern, fairly portable, and in Java.

My project team is now looking for Java developers. For those who don't know, Crossfire is a free software multi-player online role playing game that uses Java for its latest jxclient. Admittedly the site is a bit of a pain to navigate to find the jxclient, but its there, somewhere. Anyway, I forked the project before they ever came out with the jxclient, and if someone could change the jxclient to work with the modified 45 degree degree iso-metric tiles that would be great. You would be working with an already established code base and get a good look at the inner workings of a client/server set up. Its only 2d for now.
My project is called Wograld, and you can find out about the latest updates and needs at www.wograld.org.

Another thing that needs doing is the Java development for the map editor, gridarta. Gridarta needs a patch that allows it to work with the wograld tile set along with the current options of attranik, diamonin and crossfire.

If you are not up to the tasks, you shouldn't go on about how you would like to work on a java project, because java knowledge does not drop out of the sky.

Does jME3 support 2D graphics?

I forget if jME3 has a 2D specific API. But you can always do 2D graphics as textured quads in 3D. i like that approach for a lot of reasons, even if the engine in question does have 2D specific stuff.

1. It simplifies the 3D stuff so it's easier to get your feet wet without getting overwhelmed.
   
2. It gives you access to all the neat 3D features of the engine that you might not have access to in a 2D API.
   
3. When you decide to jump over to 3D you'll already be familiar with all the classes and stuff you need.
   

I worked on a 2D game in jME3 and it was really nice because I could place all the quads in a 3D scene for automatic parallax scrolling without even needing to think about it. The project died pretty quickly, unfortunately.