The Common Development and Distribution License (CDDL) is a free and open-source software license, produced by Sun Microsystems, based on the Mozilla Public License (MPL). Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary. In 2005 the Open Source Initiative approved the license. The Free Software Foundation (FSF) considers it a free software license, but one which is incompatible with the GNU General Public License (GPL). Terms Derived from the Mozilla Public License 1.1, the CDDL tries to address some of the problems of the MPL. Like the MPL, the CDDL is a weak copyleft license in-between GPL license and BSD/MIT permissive licenses, requiring only source code files under CDDL to remain under CDDL. Unlike strong copyleft licenses like the GPL, mixing of CDDL licensed source code files with source code files under other licenses is permitted without relicensing. The resulting compiled software product ("binary") can be licensed and sold under a different license, as long as the source code is still available under CDDL, which should enable more commercial business cases, according to Sun. Like the MPL the CDDL includes a patent grant to the licensee from all contributors ("patent peace"). However, in section 2.1(d), the patent grant is lost if the code implementing a patented feature is modified. History The previous software license used by Sun for its open source projects was the Sun Public License (SPL), also derived from the Mozilla Public License. The CDDL license is considered by Sun (now Oracle) to be SPL version 2. The CDDL was developed by a Sun Microsystems team (among them Solaris kernel engineer Andrew Tucker and Claire Giordano), based on the MPL version 1.1. On December 1, 2004 the CDDL was submitted for approval to the Open Source Initiative and was approved as an open source license in mid January 2005. The second CDDL proposal, submitted in early January 2005, includes some corrections that prevent the CDDL from being in conflict with European Copyright law and to allow single developers to use the CDDL for their work. In 2006, in the first draft of the OSI's license proliferation committee report, the CDDL is one of nine preferred licenses listed as popular, widely used, or with strong communities. While the Free Software Foundation (FSF) also considered the CDDL a free software license, they saw some incompatibilities with their GNU General