Sun Microsystems is trying a new way to share its Java server software, launching a project called GlassFish that lets outsiders tinker with the project's source code but that stops well short of making it actual open-source software.

Sun quietly launched GlassFish on June 6 and plans to discuss it at its JavaOne conference, which begins next week in San Francisco. The project makes the Sun Java System Application Server Platform Edition 9 available under the Java Research License (JRL), which grants some access to source code but prohibits full open-source privileges, such as permission to redistribute the software or use it beyond research projects.

"GlassFish is a window and entry point into Sun's development process where community members can review source code, submit improvements, and join in technical discussions," Sun said on the Web site. "GlassFish is a renewed partnership between Sun and the larger enterprise Java community."

Or perhaps a renewed effort by the company that invented Java to make its Java application server more relevant. Sun's application server has not attained the popularity of rival products from IBM, BEA Systems and JBoss. In a 2003 effort to boost the program's fortunes, Sun started giving away the basic Platform Edition for free.

Application server software, widely used by banks and other sophisticated Internet operations, lets the same Java program run on servers using a wide variety of processors and operating systems.

The GlassFish move follows Sun's $50 million "share" campaign and its first major moves making its Solaris operating system an open-source project. But GlassFish still isn't open-source software.

Software governed by the JRL "is only for initial research and development projects," the license terms say. "If you decide to use your project internally for a productive use, and/or distribute your product to others, you must sign a commercial agreement and meet the Java compatibility requirements."

Sun would be better off putting Java under a real open-source license, said Burton Group analyst Anne Thomas Manes. "The JRL, from my perspective, is Sun's way to try to generate a community to fix bugs and create test cases and add value to the Java platform for free," but it doesn't grant outsiders rights in exchange for those labors, she said.

Sun for years has struggled to relax its Java grip without running the risk that others could introduce incompatibilities that lead to different, incompatible versions. It has attracted numerous companies to collectively control Java in a group effort called the Java Community Process. Sun continues to warn of the dangers of incompatible Java.

A better approach, Manes believes, would be to release control of the Java source code, controlling the compatibility problem by permitting use of the Java brand only with compatible versions.

IBM, a major Java partner, has called for open-source Java, but Sun Chief Executive Scott McNealy responded with the opinion, "They have Java envy."

A significant open-source rival already has disparaged Sun's GlassFish effort: JBoss CEO Marc Fleury, whose open-source Java software is widely used.

On his blog, Fleury criticized the license as "yet another Sun invention," then added, "it is irrelevant what kind of licenses they use, since the whole thing is irrelevant anyway." He recommended watching the movie "Harold and Kumar Go to White Castle" as more interesting.

GlassFish isn't the first time Sun has let others see the application server source code, but it does mean a less complicated mechanism. For years, Sun offered Java source code under the Sun Community Source License, or SCSL, a license that has separate provisions to accommodate research use, internal use and commercial sales.

Joe Keller, vice president of marketing for Java Web services and tools, said the Java code also will be available under the Java Distribution License (JDL) for those who want to distribute the software. Offering the JRL and JDL for specific areas is simpler than one multiple-use license, he said. "We are making them simpler and easier to read," Keller said.

And the GlassFish project isn't just about seeing the software, but also about influencing it. "It is a way for us to get closer to the developer community by responding to their request to allow them to see the code and have a hand in the evolution," Keller said.

Glass fish are aquarium dwellers known for their see-through skin, but the GlassFish project is far from transparent compared with many open-source projects. Its mailing lists and frequently asked question pages are only available to those who sign the license and log in.

But Sun is offering some public information. For example, the company has published detailed instructions on building the software using Sun's open-source NetBeans development tools.