Java enterprise server required only if you have java applications. Basic java is included with Solaris 10 i.e. compiler and other stuff.
GUI has nothing to do with Java enterprise server. Your CDE desktop depends upon your Graphics card, driver and monitor. What card you have? Did your card get recognized by Solaris? Lemme know..
Difference between Solaris and Linux, both are now free.
Here is link
http://sunflash.sun.com/articles/83/...sysadmin/14025