Open source, pure Java physics / dynamics library [closed]

Question

I'm looking for a lightweight, pure Java physics engine to do some simulations for robotic motion control.

My requirements:

• Rigid body physics
• Joint constraints and forces
• Convex object collision detection
• Lightweight, pure Java so it can be embedded in my application
• Ability to run simulations quickly
• Handles 50-100 objects comfortably
• Open source

Rather than reinventing the wheel, can you recommend any existing libraries that would fit the bill?

p.s. I have Googled already - I'm just keen to get honest opinions from people who have already used or implemented such things!

Answer 1

I have used JBullet and JBox2D. They both are good libraries. JBox2D is more actively being changed, but JBullet has slightly larger base.

Just for fun, I was trying to simulate an old physics problem recently, for which I posted the results here.

Answer 2

I would also use JBullet, though its been a couple of years since I last worked with it.