Actually I should name this topic "Netbeans and Nimbus Look & Feel (L&F)" but that would eliminate many search terms that use word "theme" instead :)
To set your Netbeans, in my case it's 6.5, to use the new Nimbus theme, just look under your Netbeans installation folder/etc/netbeans.conf file. It is usually located at C:\Program Files\NetBeans 6.5\etc\netbeans.conf. Then just append --laf Nimbus to netbeans_default_options.
So it looks like this:
...Then save the file and restart your Netbeans, and proud of your new Netbeans Nimbus theme!
# command line switches:
netbeans_default_options="-J-Dorg.glassfish.v3.installRoot=\"C:\Program Files\glassfish-v3-prelude\" -J-Dcom.sun.aas.installRoot=\"C:\Program Files\glassfish-v2ur2\" -J-client -J-Xverify:none -J-Xss2m -J-Xms32m -J-XX:PermSize=32m -J-XX:MaxPermSize=200m -J-Dapple.laf.useScreenMenuBar=true -J-Dsun.java2d.noddraw=true --laf Nimbus"
# Note that a default -Xmx is selected for you automatically.
...
Note:
- To edit the netbeans.conf file under Windows, you may need editor that capable of editing unix text file. I recommend using Netbeans itself to edit this file instead of Notepad.
- If you want to change the theme back to default then you can just remove the added options from netbeans.conf file. I recommend you to bookmark this page so you will not forget where to set this option :P