Here are some screenshots from a JFX demo of a simple 2D particle system.
Since I'm not interested in deployment issues, there is no WebStart link (yet). Download the source code and run the script org.trelle.fx.ParticleSystemDemo.fx.
Basically, the particle systems moves anything that is a Node along a calculated path (see the above image). The path depends on the origin of the particle system, an initial force vector, some random deviation and an optional gravity vector. Besides the motion, a particle can (but doesn't have to) easily interpolate the color (including opacity) of the attached node.