Apache License

The Apache License (Apache Software License previous to version 2.0) is a free software / open source license authored by The Apache Software Foundation (ASF). All software produced by the ASF or any of its projects or subjects is licensed according to the terms of the Apache License. Some non-ASF software is licensed using the Apache License as well. The Apache License (versions 1.0, 1.1, and 2.0) require preservation of the copyright notice and disclaimer, but it is not a copyleft license - it allows use and distribution of the source code in both open source and closed source software.

Apache License 1.0

This is the original Apache License which applies only to older versions of Apache packages (such as version 1.2 of the Web server).

Apache License 1.1

The 1.1 version of the Apache License was approved by the ASF in 2000: The primary change from the 1.0 license is in the 'advertising clause' (section 3 of the 1.0 license); derived products are no longer required to include attribution in their advertising materials, but only in their documentation.

Apache License 2.0

The ASF approved an update to the Apache License in January, 2004. The stated goals of the license included making the license easier for non-ASF projects to use, improving compatibility with GPL-based software, allowing the license to be included by reference instead of listed in every file, clarifying the license on contributions, and requiring a patent license on contributions that necessarily infringe a contributor's own patents.

GPL compatibility issue

The Free Software Foundation considers all versions of the Apache License incompatible with the GNU General Public License. About version 2.0 of the Apache License, they say "The Apache Software License is incompatible with the GPL because it has a specific requirement that is not in the GPL: it has certain patent termination cases that the GPL does not require. (We don't think those patent termination cases are inherently a bad idea, but nonetheless they are incompatible with the GNU GPL.)" [1]

The Apache Software Foundation is still trying to make its own determination about whether the Apache License 2.0 is compatible with the GPL as quoted here.

Selected programs released under an Apache License

• Apache Ant: Java build tool
• Apache Axis: SOAP implementation
• Apache HTTP server along with some of its modules
• Apache Xindice: database server
• AxKit: XML application server
• Jakarta Tomcat: Java servlet and JSP container
• JXTA: peer-to-peer framework
• SpamAssassin: spam mail filter
• Xalan: XSLT processor
• Xerces: XML parser

Well over 1000 non-ASF projects located at SourceForge are using the Apache License.

External links

• Apache Licenses