Just read it on Groklaw

Sun believes deeply in creating communities and sharing innovations and technologies to foster more participation. Today in a historic move, Sun is opening the door to greater innovation by open sourcing key Java implementations-Java Platform Standard Edition (Java SE), Java Platform Micro Edition (Java ME), and Java Platform Enterprise Edition (Java EE)-under the GNU General Public License version 2 (GPLv2), the same license as GNU/Linux.

Love it or hate it, I believe the GPL has been responsible for an improvement in the computing world. GCC is a defacto standard toolchain in embedded work. The internet is now available world wide. This would not have happened were it not for the GPL/free software movement. Sun is doing everyone a favor. Their market is NOT selling Jav, it’s selling boxes! Everything else is an enabler, be it Java or SunOS.
Is the GPL be all, end all of licenses? Of course not. It is not necessarily appropriate for all things. Our products are specialized, with a small (compared to Microsoft Word) market and only a few competitors. It makes no sense for such a product to be open sourced. The reality is, unless you have address a large problem or segment, no one is going to look at your code anyway!