SpringInterpolator is an interpolater for animations. It is "reversed-engineered" from facebook's rebound library (I did not look at their code!). The main component of this project is an ordinary differential equation of second order and a Runge-Kutta-4 solver. Details can be found in my blog article.
To use this code implement the listener interface. Also take a look at the example application.
SpringInterpolator interpolator = new SpringInterpolator();
interpolator.addListener(this); // to receive the update events
interpolator.setFinalPosition(true); // causes the system to oscillate