Technopolies animation is simplier than skeletal (Cal3D ) or mesh animaton (which is supported by JPCT).
I used rot angles between body parts to define each frame. Then rotate all specified parts to some interpolated values on playback.
Animation editor is a visual tool for recording/previewing animations.
The pros of using own animations framewor are that it is really simple and lightweight. The cons are that you cannot mix several animations for same body parts (while it is still possible to mix separate animations for, say legs, arms and chest).
You may also want to check Cal3D as it should be more mature (in fact i am looking into switching to it someday on low priority), try googling for Fuze3D and java port of Cal3D