When I started using Netbeans (on Ubuntu Linux), and after starting to like it really quickly (it has some features Eclipse lacks, or requiers plugins I don't know about). But when I started writing code in it, I very quickly came across the problem that Netbeans didn't respond to "Alt Gr" key combinations.
It not only did not respond to the so called "dead keys", it even didn't want to type {, which is on my Belgian azerty a combination with Alt Gr. Obviously, programming Java without braces is just impossible. After a few hours of googling, and finding lots of bugrepors on java Swing not having "dead key support", I finally came across a solution: using the environment variable
AWT_TOOLKIT=MToolkit
Netbeans accept the Alt-Gr combinations. I made a bash script launching netbeans with that variable, and adjusted the .desktop file to run that script.