The Apache Software Foundation's battle with Sun Microsystems stepped up a gear last week as the open source community struggled to loosen Sun's cast iron grip on the Java platform.

The group, which represents open source developers, issued a statement last week which called on Sun to discontinue licences prohibiting Java compatible open source implementations, and make compatibility testing more accessible.

If accepted by Sun, the changes could take effect as amendments to the Java Specification Participation Agreement (JSPA), which is the legal agreement members sign with Sun when joining the Java Community Process.

The tension between Sun and the open source community has been rising since September last year when Lutris was denied certification for Java 2 Enterprise Edition (J2EE) compliance in its Enhdra enterprise application server because it is an open source product.

"We attempted for more than a year to get an open source compatible licence for J2EE but have not been successful in this regard," the company said at the time. The result was that the Enhydra project was put on ice.

JBoss, developer of a major open source Enterprise JavaBeans application server, responded with assurances that its product would still be available under an open source licence.

More than four months later Sun still hasn't certified JBoss as J2EE complaint, despite JBoss' assurance that it is, again because the software is open source.

OnJava.com, an independent source wire for enterprise Java developers, recently accused Sun of "sabre-rattling to scare off others who might want to do open source implementations of J2EE technologies".

In a recent article for TheServerSide.com, Karen Tegan, director of J2EE compatibility and platform services for Sun, said: "The J2EE compatible brand has achieved significant momentum over the past two years, and we want to make sure that any open source efforts don't impact the viability of that effort."

The Apache group replied: "In other words, Sun doesn't give a hoot about whether J2EE licensing restricts open source J2EE products (in case you missed it, it does).

"Thus, the Apache Software Foundation's involvement in the Java Community Process is simply an advertising statement for Sun to claim that it has a 'vision which uses open standards and non-proprietary interfaces'."

Apache's full stance on the JSPA can be read here.