Java plataformer, before unity

I said that i would first make an 2d plataformer in java, then a plataform, in unity with c#. I keep my word... Well making physics in java was not easy, took a lot of effort, but a the end i think that i still managed it to some degree. Now it is unity turn, but no one cares anyway, well but im still doing it. IT IS GOING TO BE FOR FREE TOO.