Classpath Exception not included in the mobile edition
Posted Aug 18, 2010 10:46 UTC (Wed) by paulj
In reply to: Classpath Exception not included in the mobile edition
Parent article: A very grumpy editor's thoughts on Oracle
That's not true, OpenJDK is under a GPLv2 + "ClassPath Exception" licence. Here's the text of that exception:
"CLASSPATH" EXCEPTION TO THE GPL
Certain source files distributed by Sun Microsystems, Inc. are subject to
the following clarification and special exception to the GPL, but only where
Sun has expressly included in the particular source file's header the words
"Sun designates this particular file as subject to the "Classpath" exception
as provided by Sun in the LICENSE file that accompanied this code."
Linking this library statically or dynamically with other modules is making
a combined work based on this library. Thus, the terms and conditions of
the GNU General Public License cover the whole combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent modules,
and to copy and distribute the resulting executable under terms of your
choice, provided that you also meet, for each linked independent module,
the terms and conditions of the license of that module. An independent
module is a module which is not derived from or based on this library. If
you modify this library, you may extend this exception to your version of
the library, but you are not obligated to do so. If you do not wish to do
so, delete this exception statement from your version.
That exception makes it explicit that the ClassPath libraries so marked can be linked with other applications without affecting the licensing of the application.
The JavaME edition has some additional libraries, specific to mobiles obviously, which do NOT offer this exception - they're GPL only. Hence why many users of JavaME chose to get a proprietary licence from Sun. Google do not use those APIs anyway, AFAIK. I.e. it does seem that there were no licensing obstacles to Google using the OpenJDK, at least in terms of wanting to avoid applications having to be GPLed (Google might have started its Dalvik work while Sun were still in the process of GPLing the JDK - anyone remember the exact timeline?).
Given that Google generally went out of its way to avoid having any GPL code in Android, it seems that their motivation was simply to avoid being restricted in any way by copyleft. I wonder if that choice was made on a rational basis, or out of less rational, base GPL hatred/fear.
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