I posted earlier today about the bug in Ubuntu Feisty that causes Java apps that use GUI to fail. It turns out it is an upstream bug in Java 6 itself that is brought out by new xcb code in X11. As of now, it is unclear if Ubuntu will choose to downgrade X11 packages or wait until Sun or someone else fixes the bug in the Java.

Not wanting to uninstall Feisty and revert to Edgy or play around with manually downgrading libraries, the quickest work around to continue coding in Netbeans on my dual-head Feisty box has been to simply running Netbeans on another computer and display it to Feisty’s screen.

On box with newer X11 libraries that break Java (in this case running Feisty) we allow computer with hostname edgy to connect to the display.
user@feisty$xhost +edgy

On box with functioning Java 6, not broken by newer X11 libraries, we tell the computer where to send the GUI output of X11 programs.
user@edgy$export DISPLAY=edgy:0
user@edgy$netbeans

Please note that these directions assume dns is properly set up so that feisty and edgy can be resolved to their proper IP addresses. If you do not have DNS or the hosts file set up properly, please substitute the IP address for the hostnames.