Oracle made available this week a preview of the open source JDK (Java Development Kit) 7, enabling developers to kick the tires on an upcoming upgrade to the Java platform. But some observers are concerned about a so-called "draconian" licence for the kit.

JDK 7 serves as one component of Java SE 7 (Java Platform, Standard Edition 7), or Java 7. A planned Java runtime is the other critical component.

"This milestone is intended for broad testing by developers, deployers and end users," said Oracle's Mark Reinhold, chief architect of the company's Java Platform Group, in a blog post. "We've run all tests on all supported platforms and haven't found any glaring issues. We've also ?xed 456 bugs since reaching the Feature-Complete Milestone back in January."

But some persons commenting on Reinhold's blog were disappointed with licensing terms.

"I wanted to try this out. But it has a draconian restrictive licence [attached] to it. If you decline to accept that, you cannot download. Is there any reason to use such an anti-social licence that prevents usage by the larger community that helped you build this upon the GPL'ed OpenJDK code base?" one commenter asked.

Another commenter referenced previous Oracle controversies related to the OpenOffice productivity suite and the Hudson integration server, in which Oracle, since acquiring Sun, has had disagreements with supporters of those projects. The commenter also noted Oracle's rocky relationship with the Apache Software Foundation.

"Well, it looks like Oracle has really figured out how to annoy and harass developers after the Apache, the OpenOffice and the Hudson disaster," the commenter said. "A draconian licence and a totally unworkable bug tracker, where the landing page tries to sell me paid support."

An Oracle representative declined to comment on criticisms of the licensing terms. But in a blog comment attributed to Reinhold himself, the licence was called "less than ideal" and says Oracle will look into revising it. License and bug tracker terms were the same as what Sun offered.

"Contrary to what you may think, Oracle does not have an evil master plan to 'annoy and harrass developers,'" Reinhold said.

Java SE 7, with improvements for dynamically typed languages and new I/O APIs, is due to be completed later this year. Multi-core processor functionality has been highlighted as well.

"If you've been watching JDK 7 development from the sidelines, then now is a great time to download a build and take it for a spin. See if your favourite project still compiles and runs, see if it runs any faster than before, or try out one of the many new features," Reinhold said.

The JDK preview is available at the Java website.