SwingSet2 doesn't work with GTK L&F on JDK7 and throws NPE. Its error message is as follows:
  Failed loading L&F: com.sun.java.swing.plaf.gtk.GTKLookAndFeel
  java.lang.NulPointerException

It works fine on 6u11.
I'm using Solaris 10 with CDE.
I changed my desktop environment from CDE to GNOME/Solaris 11. Unfortunately, NPE is thrown even on GNOME.