i would like to use processing as render template to see how it works, but if is using java 2d and am already using that, then i think wont be much useful.
Processing can use Java2D, OpenGL, JavaFX, JavaScript Canvas, and more. It depends what renderer you set it to. Make sure to use P2D or P3D for OpenGL - the default is Java2D.
Of course, the best way to use Processing is in Praxis LIVE, but then, I’m biased! 
@nsigma already covered it: Processing uses a bunch of different things depending on which renderer you choose.
But even if you use the Java2D renderer, Processing gives you a bunch of stuff on top of Java2D: a reliable 60fps render loop, easier event functions, a simplified IDE, and access to all of the functions in the Processing API.
The best thing you can do is try it out. Put together a few hello world programs and see if you like it.
Also note that you don’t have to use PDE. If you already have an IDE of choice, I’d stick with that and use Processing as a library, once you get past the basics. PDE is pretty dire for all but the most simple projects!
… of course, the IDE of choice should be NetBeans, but then again I’m biased.
thanks, my IDE is Netbeans, and i want to use with it, seems interesting maybe i can use processing rendering powers indise my application, thanks guys you helped me a lot.
Cool! ;D I’m involved with the new Apache NetBeans project, so good to know. New release should be out soon.
You should definitely give Praxis LIVE a try too, then. Should feel familiar. It’s a NetBeans-based IDE with the ability to live-code Java, and has the Processing libs built in.