How do I tween in Java?

I'm looking into making a 2D game in Java and I've run into a problem with animation: how do I do tweening in Java? Are there any libraries or maybe something I can find bindings for?

Also, please understand that I do not want to simply move an image, I want to do morphing in a way that when making drawings for animation I can use a few keyframes to fill in the in-between frames to generate the animation.