Sun JDK vs OpenJDK - Sun JRE vs OpenJDK JRE

Dalibor Topic Dalibor.Topic at Sun.COM
Sat Sep 13 13:44:31 UTC 2008

Frans Thamura wrote:
> anyone have a list that compare Sun JDK with OpenJDK and also OpenJDK
> JRE with "Sun JRE
There is no OpenJDK JRE, specifically. The comparison that makes sense
is one between
Sun Java SE 6 JDK and the OpenJDK jdk6 project.

Differences are:

a) licenses:

OpenJDK jdk6 is Free Software, Sun's Java SE 6 JDK downloads are not, in
particular because
* they contain proprietary third party components (also known as
'encumbrancies'), that wouldn't be trivial to rip and replace in a
stable release series
* they contain Sun's own proprietary code that has not been / could not
be opened up so far

b) deployment code:

OpenJDK does not have a plugin or a webstart implementation.

The code Sun has in the deployment area has been largely rewritten for
Java SE 6 update 10, and the new code,
being a significant chunk of software, requires a new run through the
business decision making process on Sun's side.

Meanwhile, the IcedTea project augments the OpenJDK jdk6 project with
independent implementations
of the plugin and webstart, called gcjwebplugin and netx. Those
independent implementations have a different
set of strengths and weaknesses from Sun's implementations: they work on
64 bit Linux, for example, a platform
that hasn't been supported by Sun's own plugin yet. On the other hand,
gcjwebplugin currently lacks an
adequate Java-JavaScript integration that's required by some applets to
execute as well as expected.

c) bundled code:

Sun's Java SE 6 download comes with a lot of (third party) software
bundled in, for example
Java DB, Rhino, Visual VM, etc. OpenJDK jdk 6 project leaves such
software out as much as possible,
concentrating on the necessities required for a compatible
implementation of Java SE 6.

IcedTea augments OpenJDK jdk6 with Rhino, though there is still work to
be done on making the integration seamless.
There is also some initial work on integrating VisualVM into IcedTea.

d) encumbered code:

The Java SE 6 JDK still mostly contains the ~4 % of encumbered, i.e.
third party code that couldn't be licensed as
Free Software, and  was replaced by open source implementations from the
community in OpenJDK 6.

dalibor topic

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