Today, I installed indiana preview release (get it here) on an existing solaris partition. And the installation time is a little longer than I expected. The only one issue I met is, after the installation, grub was not installed properly. So, we have to use
installgrub(1) to reinstall it on MBR. The root password on livecd is "opensolaris".
Currently the software package repository is still small (have a look at http://pkg.opensolaris.org.) Anyway, it's the first step (also an important step), and I believe it will lead opensolaris to bigger success.
BTW, you may try to install Glassfish packages via IPS, refer to http://wiki.updatecenter.java.net/Wiki.jsp?page=MultiPlatformIPSPrototype.