Is it possible to recompile the kernel or any userland on Solaris

Hi I am a FreeBSD user
Just want to know is it possible to recompile kernel or any other userland in Solaris 10 or OpenSolaris?

I want check out this UNIX OS which has Flash 9 support :smiley:

You can build from source most of this with OpenSolaris. Follow the instructions here: ON Downloads Page at OpenSolaris.org

Thanks:D