Content delivery server open sourced by Sun

Sun continues to walk on its open source path and now Content Delivery Server (CDS) is being open sourced. Sun will be offering two versions- the existing commercial product and an open sourced version. This will surely be increasing the popularity of Sun among the developer community.
Aimed at wireless carriers, it is a mobile content delivery and management platform. It has been used for selling games, ring tones and multimedia assets to smart phones. Sun will be offering Content Delivery Server under the Common Development and Distribution License (CDDL). I was just wondering why it didn't go for the General Public License, probably the reason for opting for CDDL could be that contribution of derivative work to the community is not required. It may happen that CDS might be ultimately opened under GPL similarly like Java ME and SE.