I started making this isometric tower defense prototype. This is not supposed to be a full game, but rather a play ground to try to find different code structures than to what I’m used to and get a better understanding of isometric game programming.
I also wanted to test text rendering library that I made on more machines. If the application doesn’t work, please paste the stack below 
So far all I have made is a 20x20 tile level. You can increase / decrease elevation by pressing X and C on the keyboard, which will change the elevation of the currently hovered tile. You can also place buildings by dragging a mouse while holding down left button and selecting some tiles. If you want to delete the building, right click on the building and it will be removed. Right now there the following patterns for buildings: 1x1, 2x2, 3x1, 1x3.
You can move using ASDW.
The prototype is very NOT optimized performance wise, so there might be performance drop on machines that don’t have a proper graphics card (I had huge FPS drop on laptop with integrated-in GPU).
On the final note, this is only supposed to work on WINDOWS for now.
Here is the link. Just extract the folder to wherever you want and run the td.jar file inside!
http://www.mediafire.com/download/29ih1s6wln0al80/export.zip
–edit
whoops i just realized i put to .rar so now i changed link to .zip
