http://www.vis.uni-stuttgart.de/glsldevil/ is a free program to debug glsl code. Has anyone tried it succesfully with JOGL?
yeah i tried it, but not successfully. but it also didn’t work for “normal” openGL apps.
however gDebugger (commercial) works very well with jogl.
http://www.gremedy.com/
I have tried gDebugger succesfully as well, and is a very useful tool. gDebugger, however, does not support debugging of glsl programs.
I would like to find out if it is glslDevil or JOGL that is the problem.
i suspect it is glslDevil, since it seems to be softwarewiese in quite an alpha-state.
if you want to debug just glsl-code, then have a look at
http://www.opengl.org/sdk/tools/ShaderDesigner/
it also quite outdated, but still works.
Thank you for that tip. 
But ShaderDesigner doesn’t seem to be as powerful as glslDevil. glslDevil lets you step through your code and inspect variables while your program is running.