Common Development and Distribution License
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Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary. The Free Software Foundation considers it a free software license that is incompatible with the GNU General Public License (GPL). The incompatibility arises from a complex interaction of several clauses that the CDDL inherited from the MPL. The CDDL was submitted for approval to the Open Source Initiative on December 1, 2004 and was approved as an open source license in mid January 2005. 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.
The previous license used by Sun for its free software/open source projects was the Sun Public License (SPL), also derived from the Mozilla Public License. The CDDL license is considered by Sun to be SPL version 2.
Example products released under CDDL:
- OpenSolaris (including DTrace, initially released alone, and ZFS)
- NetBeans IDE and RCP
- Project DReaM
- Bourne shell
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.
GPL incompatibility 
In the words of Danese Cooper, who is no longer with Sun, one of the reasons for basing the CDDL on the Mozilla license was that the Mozilla license is GPL-incompatible. Cooper stated, at the 6th annual Debian conference, that the engineers who had written the Solaris kernel requested that the license of OpenSolaris be GPL-incompatible. "Mozilla was selected partially because it is GPL incompatible. That was part of the design when they released OpenSolaris. [...] the engineers who wrote Solaris [...] had some biases about how it should be released, and you have to respect that."
Simon Phipps (Sun's Chief Open Source Officer at the time), who had introduced Ms. Cooper as "the one who actually wrote the CDDL", did not immediately comment, but later in the same video, he says, referring back to the license issue, "I actually disagree with Danese to some degree", while describing the strong preference among the engineers who wrote the code for a BSD-like license, which was in conflict with Sun's preference for something copyleft, and that waiting for legal clearance to release some parts of the code under the then unreleased GNU GPL v3 would have taken several years, and would probably also have involved massed resignations from engineers (unhappy with either the delay, the GPL, or both—this is not clear from the video). Later, in September 2006, Phipps rejected Cooper's assertion in even stronger terms.
The claimed incompatibility was also source of a controversy behind a partial relicensing of cdrtools to the CDDL (which had been previously all GPL), which was declared legally undistributable by the Debian project because the build system was licensed under the CDDL, even though the GPL requires that all scripts required to build the work to be licensed freely but not necessarily under the GPL, thus not causing an incompatibility that violates the license. Jörg Schilling, the author, claims smake to be an independent project and therefore not violating the GPLv3. (In the mean time, much of the cdrtools code has also been re-licenced under the CDDL.)
See also 
- Free software licence
- Mozilla Public License
- BSD License
- GNU Free Documentation License
- GNU Lesser General Public License
- GNAT Modified General Public License
- List of software licenses
- "Various Licenses and Comments About Them - Common Development and Distribution License". Free Software Foundation. Retrieved 2006-12-31.
- "Can code licensed under the CDDL be combined with code licensed under other open source licenses?". OpenSolaris FAQ: Common Development and Distribution License (CDDL). OpenSolaris.
- "MPL / GPL Incompatibility". Retrieved 2007-12-03.
- First draft of OSI's license proliferation report
- "SPL to CDDL as of NetBeans 5.0 - Why change licenses?". NetBeans. Retrieved 2006-12-31.
- Danese Cooper (2006). OpenSolaris and CDDL discussion at Debconf 2006 (Ogg Theora). Event occurs at 27:26. "Mozilla was selected partially because it is GPL incompatible. That was part of the design when they released OpenSolaris. [...] the engineers who wrote Solaris [...] had some biases about how it should be released, and you have to respect that" (alternate URL, see 27:27 through 28:24)
- Simon Phipps (2006). OpenSolaris and CDDL discussion at Debconf 2006 (Ogg Theora). Event occurs at 13:00. "...we have got Danese Cooper in the room, and she is the one who actually wrote the CDDL..."
- Simon Phipps (2006). OpenSolaris and CDDL discussion at Debconf 2006 (Ogg Theora). Event occurs at 36:00. "I actually disagree with Danese to some degree..."
- Phipps, Simon. "Re: Danese Cooper claims CDDL made incompatible with GPL on purpose". Retrieved 2008-11-23.
- "The GNU General Public License". Retrieved 2009-10-24.
- Die GPL kommentiert und erklärt Online-Version
- Jonathan Corbet. "cdrtools - a tale of two licenses". Retrieved 2007-08-04.
- Jörg Schilling. "Linux controversy". Retrieved 2009-10-26.
- Common Development and Distribution License (CDDL) Information, archived from the original on 2009-03-04
- CDDL 1.0, archived from the original on 2009-03-05
- "CDDL 1.0 copy at opensource.org". Retrieved 9 April 2013.
- Redline diffs between MPL1.1 and CDDL, p. 9, archived from the original on 2009-03-04
- Summary description of changes, archived from the original on 2009-03-04
- Detailed description of changes, archived from the original on 2009-03-04
- FAQ on CDDL on Open Solaris Site
- The Common Development and Distribution License, Linux Weekly News Editorial
- CDDL Analysis from a DFSG perspective, and Opinion Piece
- Free software licenses