CDDL and GPL legal incompatibility
| Author | Sun Microsystems |
|---|---|
| Latest version | 1.0 |
| Publisher | Sun Microsystems |
| DFSG compatible | Yes |
| FSF approved | Yes |
| OSI approved | Yes |
| GPL compatible | No |
| Copyleft | Limited |
| Linking from code with a different license | Yes |
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). In 2018, according to Black Duck Software the CDDL is the 16th most popular FOSS license, after the AGPLv3 (both, and more, with less than 1% use).
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").
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.
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