Modeling and Simulation in Java

I am looking into using Java to be able to model/simulate (MODSIM) discrete and continuous systems in the areas of traffic modeling, birth/death process, spread of disease etc. I have a working knowledge of Java. I have a good grasp of calculus and differential equations.

I am looking for a MODSIM software that is:

a)Free and Java based

b)Does most of the graphics/animation and allows for 3D Visualization

c)Allows for Java Extensions

I looked at the following software:

a)NetLogo - allows Java extensions but is based on writing procedures.

b)Greenfoot - based in Java and allows for Java Extensions

For modeling the kind of systems that I have mentioned in the first paragraph of my question:

1) Is Greenfoot a good choice ?

2) Wh开发者_JAVA百科at other Java based MODSIM tools would you recommend?

Thank you! Hop

If you are interested in agent based simulations, I'd recommend RePast. Anyway, I've recently been searching for something similar and unfortunatelly I didn't find anything interesting. We've ended up writing our software at our university.

PS: Never heared of Greenfoot, sorry