You should be able to improve the font rendering, but it will never be like the one in Gedit. Usually all java applications using Swing have that weird rendering. If you use Eclipse, for example, the font rendering should be correct.
Font rendering can be changed in
sudo gedit /etc/netbeans.conf
and at the end of
netbeans_default_options (between the quotation marks) add this:
where option can be "on", "gasp" or "lcd". You can get the full list here.
Try all those and see which one gives you best look. Hope it helps.
i don't have Netbeans installed right now to test, but depending on the way you have installed it
netbeans.conf can be located somewhere else.