Skip to main content

Check It Out

Posted by editor on August 10, 2007 at 10:38 AM EDT

JCK license available for OpenJDK and derivatives

Compatibility testing has been one of the most contentious issues since the announcement of Sun's GPL release of its Java implementation. It's one thing to use the code, and quite another to be able to say that your runtime is "Java"-compatible. The assertion of compatibility has to be backed up to have credibility, yet some have complained that it's inconsistent to have the implementation open and the Technology Compatibility Kit (TCK) not be.

Yesterday, Sun announced the immediate availability of the OpenJDK Community Technology Compatibility Kit (TCK) License. In the announcement, they say:

The OpenJDK Community TCK License will enable developers to test the compatibility of their contributions to the OpenJDK project. It will also allow distributors to test complete implementations that are substantially derived from OpenJDK and distributed under GPLv2. Organizations or individual developers that use the OpenJDK Community TCK License and then successfully pass compatibility testing, will also have the option of branding their implementation with Sun's "Java Compatible" trademark and logo.

Rich Green's blog, Score Another for Clarity and Transparency, explains the value of this move:

So today we're taking the next step—one I discussed at this year's JavaOne conference. Sun is making the Java SE JCK—the TCK compatibility tests that determine whether an implementation faithfully conforms to the Java SE specification—available to the Java GPL software community using a license that continues to protect the Java compatibility promise while respecting the values of free software. This means that OpenJDK implementors, including GNU/Linux distributions can test free Java implementations based on code released under the GPL in the OpenJDK community, and validate that their implementations are compatible with Java. We're empowering distributors of free Java implementations to be part of the "Write Once, Run Anywhere" promise, while fulfilling all of their obligations under the GPL.

You can check out the entire OpenJDK Community TCK License V. 1.0 as a PDF, or look over the newly-updated TCK's section in the Open-Source Java FAQ. Probably the most important point to understand is that the license covers the GPL'ed OpenJDK and its derivatives, not Java implementations that are licensed through other means (such as the commercial license used by various vendors).

There are already some interesting blogs about the JCK license. In OpenJDK has a JCK License, Simon Phipps writes, "I think the license is a huge achievement. It gives OpenJDK and the communities around it very easy access to the JCK, far easier than I feared would be possible. We got rid of five whole pages of terms in the discussion process." Meanwhile, in OpenJDK JCK, Dalibor Topic considers the positive implications for OpenJDK derivatives like the IcedTea project: "While the OpenJDK license remains proprietary to avoid 'cheating' on the tests, it creates a competitive advantage for a class of free software Java implementations over their proprietary counterparts. That could be a similarly game changing move that the introduction of the JCP scholarship was."

Expect more feedback today as bloggers and other community members digest the news, look at the license, and post their thoughts...

Also in Java Today, Daniel Lopez has kicked off a series of blogs comparing different scripting languages that can be run on the JVM. In his first entry, he checks out Groovy for querying a DataSource obtained via JNDI, and finds that Groovy's great at getting through the data and building the XML, though the JNDI access is a stumbling block. In the next installment, he tries the same thing with the Rhino JavaScript implementation included in JDK 6, with similar results and faster performance. A note on the second entry says that Jython will probably be the next language evaluated in the series.

Got a question about MSA? Then save the date. August 20 - 24th is your opportunity to Ask the Experts! MSA is the Java ME optional package that defines the next generation Java ME platform. Your questions will be answered by Java ME Community Project Owners Hinkmond Wong (phoneME Advanced) and Mikhail Gorshenev (cqME), and E-ming Saung, Product Line Manager for Java ME SDKs. For more information about this event and how to participate, go to the Ask the Experts page.

In his feature article, Looking Ahead to Java 7, David Flanagan cited a list compiled by Danny Coward of possible language changes that might be part of Java 7. We've taken that list verbatim to create the the latest java.net Poll, which asks "Which proposed language change would you most like to see in Java 7?" Cast your vote on the front page, then visit the results page for current tallies and discussion.

Returning momentarily to the topic of the JCK, a question came up in the Forums, as to the announcement's applicability to Java ME. In Re: Does today's TCK announcement apply to phoneME?, terrencebarr explains, "this announcement pertains to OpenJDK. In the Java ME space things are more difficult since a Java ME implemementation typically covers by multiple JSRs (CLDC, MDIP, WMA, etc) and the TCKs for each JSR may come from different parties (such as Sun, Mototola, Nokia, etc). The decisions about those TCKs are made by the individual parties. However, because TCK access is an important topic Sun is in talks with other TCK owners and Sun is considering its options related to the Java ME TCKs it owns. No final decisions have been made yet."

Sahoo explains a problem marshalling cyclic references in Re: Infinite XML Loop. "That exception typically comes from JAXB marshaling code when it detects a cycle in the object graph. Are you returning the object from a web service? Your in-memory object probably has the bidirectional references set up, this can happen if you traverse the relationships in your code. So, instead of relying on fetch type, you should explicitly cut the cycles in the graph by setting some references null."

tarbo explains splash screen strategies in Re: help in assigning progressbar to my project. "Then you can either upgrade to 6 or you can make do with a class of your own: spawn an undecorated frame with an image as content, and draw as necessary. Append a splash.setVisible(false) to the EDT after telling the GUI to load and you should have a splash screen. It's what people did before SplashScreen became available as a class."

Our latest JavaOne Community Corner Podcast is j1-2k7-mtW02: Binding Components - Open JBI Components by Rulong Chen and Alex Fung. "OpenJBI Components are based on the industry standard JBI architecture. They are open source components developed under java.net community process. In this talk we will explore most popular OpenJBI components: Http BC, Messaging BCs (MQ and JMS), JDBC BC. Developers will have an opportunity to understand how to use these BCs to build composite applications under the OpenESB platform."

In today's Weblogs. David Herron tries to knock down some widely-held assumptions about Java-in-browser availability One of the questions/concerns about Java is, can a web site author assume that it's there? Part of the popularity of Flash or Javascript is it's in all browsers, but the belief is that Java probably is not installed.  — 

Mark Lam explains memory management in CVM: Why use the C or Java heap? "A comment in a previous blog asks why CVM keeps some data structures in the C heap instead of the Java heap. Here's the answer."

Aastha Bhardwaj announces a New (really cool) demo added to phoneME UI Labs! "Here's proof that we have indeed been busily toiling away to bring you more cool UI examples. We have just made the source to the MobileAerith demo available on phoneME UI Labs."

Current and upcoming Java Events :

Registered users can submit event listings for the java.net Events Page using our events submission form. All submissions go through an editorial review before being posted to the site.

Archives and Subscriptions: This blog is delivered weekdays as the Java Today RSS feed. Also, once this page is no longer featured as the front page of java.net it will be archived along with other past issues in the java.net Archive.



JCK license available for OpenJDK and derivatives
Blog Links >>