private int getNextKeyFrame(int index, Object[] keyFrames) {
        for (int i = index + 1; i < totalFrames; i++) {
            if (keyFrames[i] != null) {
                return i;
            }
        }
        return -1;
    }
Get the index of the next keyFrame that as a transform
@param index the start index
@param keyFrames the keyFrames array
@return the index of the next keyFrame
jme3-core/src/main/java/com/jme3/animation/AnimationFactory.java