1page.title=Licenses 2doc.type=source 3@jd:body 4<div> 5<p>The Android Open Source Project uses a few <a 6href="http://www.opensource.org/">open source initiative</a> approved open 7source licenses to enable availability of source code and to accept 8contributions from individuals and corporations.</p> 9<h2>Android Open Source Project license</h2> 10<p>The preferred license for the Android Open Source Project is <a 11href="http://www.apache.org/licenses/LICENSE-2.0">Apache 2.0</a>. Apache 2.0 12is a commercial and open source friendly open source license. The majority of 13the Android platform is licensed under the <a 14href="http://www.apache.org/licenses/">Apache 2.0 license</a>. While the 15project will strive to adhere to the preferred license, there may be 16exceptions which will be handled on a case-by-case basis. For example, the 17Linux kernel patches are under the GPLv2 license with system exceptions, which 18can be found on <a 19href="http://www.kernel.org/pub/linux/kernel/COPYING">kernel.org</a>. 20</p> 21<h2>Contributor License Grants</h2> 22<p>All <b>individual</b> contributors (that is, contributors making contributions 23only on their own behalf) of ideas, code, or documentation to the Android Open 24Source Project will be required to complete, sign, and submit an <a 25href="{@docRoot}source/cla-individual.html">Individual 26Contributor License Grant</a>. The grant can be executed online through the <a 27href="https://review.source.android.com/#settings,agreements">code review 28tool</a>. The agreement clearly defines the terms under which intellectual 29property has been contributed to the Android Open Source Project.This license 30is for your protection as a contributor as well as the protection of the 31project; it does not change your rights to use your own contributions for any 32other purpose.</p> 33<p>For a <b>corporation</b> (or other entity) that has assigned employees to 34work on the Android Open Source Project, a <a 35href="{@docRoot}source/cla-corporate.html">Corporate 36Contributor License Grant</a> is available. This version of the Grant allows a 37corporation to authorize contributions submitted by its designated employees 38and to grant copyright and patent licenses. Note that a Corporate Contributor 39License Grant does not remove the need for any developer to sign their own 40Individual Contributor License Grant as an individual, to cover any of their 41contributions which are <b><i>not</i></b> owned by the corporation signing the 42Corporate Contributor License Grant. 43</p> 44<p>Please note that we based our grants on the ones that the <a 45href="http://www.apache.org/">Apache Software Foundation</a> uses, which can 46be found on <a href="http://www.apache.org/licenses/">the Apache web site</a>.</p> 47<h2>Why Apache Software License?</h2> 48<p>We are sometimes asked why Apache Software License 2.0 is the preferred 49license for Android. For userspace (that is, non-kernel) software, we do in 50fact prefer ASL2.0 (and similar licenses like BSD, MIT, etc.) over other 51licenses such as LGPL.</p> 52<p>Android is about freedom and choice. The purpose of Android is promote 53openness in the mobile world, but we don't believe it's possible to predict or 54dictate all the uses to which people will want to put our software. So, while 55we encourage everyone to make devices that are open and modifiable, we don't 56believe it is our place to force them to do so. Using LGPL libraries would 57often force them to do so.</p> 58<p>Here are some of our specific concerns:</p> 59<ol> 60<li>LGPL (in simplified terms) requires either: shipping of source to the 61application; a written offer for source; or linking the LGPL-ed library 62dynamically and allowing users to manually upgrade or replace the library. 63Since Android software is typically shipped in the form of a static system 64image, complying with these requirements ends up restricting OEMs' designs. 65(For instance, it's difficult for a user to replace a library on read-only 66flash storage.)</li> 67<li>LGPL requires allowance of customer modification and reverse 68engineering for debugging those modifications. Most device makers do 69not want to have to be bound by these terms, so to minimize the burden on 70these companies we minimize usage of LGPL software in userspace.</li> 71<li>Historically, LGPL libraries have been the source of a large number 72of compliance problems for downstream device makers and application 73developers. Educating engineers on these issues is difficult and slow-going, 74unfortunately. It's critical to Android's success that it be as easy as 75possible for device makers to comply with the licenses. Given the 76difficulties with complying with LGPL in the past, it is most prudent to 77simply not use LGPL libraries if we can avoid it.</li> 78</ol> 79<p>The issues discussed above are our reasons for preferring ASL2.0 for 80our own code. They aren't criticisms of LGPL or other licenses. We do 81feel strongly on this topic, even to the point where we've gone out of our 82way to make sure as much code as possible is ASL2.0. However, we love all free 83and open source licenses, and respect others' opinions and preferences. We've 84simply decided that ASL2.0 is the right license for our goals.</p> 85</div> 86