Plans for OpenJDK

Our team at Red Hat has been doing some planning now that OpenJDK has been released. First, a summary of OpenJDK’s status:

What Sun has released:

• most of the 1.6-level JDK, including:

• the Hotspot virtual machine with x86 and x86_64 JITs
• the Java compiler
• most of the class libraries

What Sun hasn’t released:

• 4% of the class library code — some of the class library code is “encumbered” meaning that Sun can’t release it under the GPL. The encumbrances are in the sound system, font rasterizer, graphics rasterizer, SNMP and crypto areas.
• plugin and javaws
• a 1.5 version

The second list points the way to some of our immediate goals. Here is a list of some of the goals we decided on:

1. Packaging OpenJDK as IcedTea

   We can’t call what we ship “OpenJDK” because that’s a Sun trademark. We’ve decided on the temporary name “IcedTea”, and we can say that it’s based on code from openjdk.java.net. We’ve posted an SRPM containing the free OpenJDK sources. But it still requires non-free stuff to build, which brings us to the next goal.

2. Building with free software

   Currently OpenJDK requires openmotif, Sun’s proprietary JDK 1.6 and a bundle of proprietary “plugs” (to replace the encumbrances) to build. Our group’s first goal is to make OpenJDK buildable against a set of fully-free packages.

3. Setting up icedtea.classpath.org

   With help from some GNU Classpath community members we’re setting up icedtea.classpath.org with a Wiki, mailing list and a Subversion repository, to host the work we’ll be doing on OpenJDK. This is a temporary site where we can experiment with the OpenJDK code while Sun works out its contribution processes. The site is not complete yet.

4. Testing without the encumbrances

   Because we haven’t built OpenJDK without the binary plugs for the encumbrances yet, we don’t know exactly how it fails if they’re not present. We need to see if the result can be proposed for inclusion in Fedora.

5. Replacing encumbered bits with parts from GNU Classpath

   Once we’ve tested running without the encumbrances we’ll know where to focus our replacement efforts.

6. Testing OpenJDK interpreter on other architectures

   Since at this point we only have x86 and x86_64 JITs, platform coverage will be a problem. In the short term we should test the OpenJDK interpreter portability since it may be possible to use it as a stop-gap on the architectures for which we don’t have JITs.

7. Working with Sun on contributor license agreements, use of trademarks, self-certification and governance.

   Eventually, we’d like to ship in Fedora a certified Java implementation that we can call OpenJDK and “Java compatible”. Sun intends to make that possible through a self-certification process. Eventually we should be able to contribute code directly to the OpenJDK project — Sun has worked out the governance model it will use and is implementing a Mercurial repository.

8. Working with other Red Hat groups on OpenJDK

   We expect to work closely with other Red Hat groups on both system integration (kernel, tools, desktop, packaging) and on requests from internal “consumers” of the JDK (JBoss, Eclipse).

GCJ

We will continue to support GCJ where it is deployed, but any new work we do will be on the OpenJDK codebase. GCJ still has better architecture coverage than OpenJDK, supporting all 7 RHEL architectures where OpenJDK supports 2, but we’ve decided that the benefits of OpenJDK outweigh this advantage of GCJ, and that effort is better spent trying to get (or write, if need be) more JITs for OpenJDK.

Timelines

We don’t have definite timelines yet. We’re in an investigation stage right now, so precise timelines will have to wait until we’ve had more time to discuss the OpenJDK codebase and Sun’s timelines.