The idea is to create a stepping stone, not a Game Maker in Java. The interface and the functions are not related at all, just the way of programming. In Game Maker for example one can put a piece of code in the create event of an object. In Coffee Maker you can also do this, like this:
public class something extends GMObject
public void create()
Some Java knowledge is needed, but from knowing programming in Java to knowing how to program a game in Java is a big step, and one that I want to make smaller, if possible.
I see what you mean and I hope you will get a better result than Game Maker for 3D because I tested a first person shooter using the D3D mode of Game Maker on Gamejolt and it was extremely slow whereas the graphics were rudimentary. However, do not reinvent the wheel. If you plan some 3d support, do not write it from scratch and use an existing 3D engine. I wrote my own 3D engine in 2006 and I can tell you that it requires a huge amount of work. To sum up, I advise you to write your API above an existing engine rather than creating everything from scratch.
Driving game development in Java easier is a good idea but anyway, when something does not work as expected, you feel more comfortable when you know how the low-level layers work and it allows you to be able to repair them.