Box2D was written in C++. Someone need to do work to convert it to java.
Actually, you can create those effect without Box2D with EJS.
There are particles (which can rotate and change shape) or polygon to draw any kind of object.
What really important is give proper physics property to the object and that is the fun part to play with physics.
You just want to have fun to play with something like Box2D ,or you want to help student learn how to connect the physics to the case.
JBullet is a java library. You can include any java library and use it. Just include the jar files.