Oracle Releases JDK 8 Developer Preview

Java Standard Edition 8 (Java SE 8) isn't due until March, but Oracle has just released a preview build for testing by developers. The Developer Preview for JDK (Java Development Kit) 8, known as Milestone 8, was made available on Monday.

Mark Reinhold, chief architect of the Java Platform Group, announced the availability in his blog. "This milestone is intended for broad testing by developers," he wrote. "We've run all tests on all Oracle-supported platforms and haven't found any glaring issues. We've also fixed many of the bugs discovered since we reached the Feature Complete milestone back in June."

The principal feature of this release is Project Lambda (JSR-335), which adds closures and related features to the Java language to support programming in multicore environments. Project Lambda comprises lambda expressions, default methods, and method references to the Java programming language, and it extends the libraries to support parallelizable operations upon streamed data.

Project Lambda was one of the biggest features to slip past the Milestone 6 release in January, because of Oracle's focus on the Java-based browser security vulnerabilities that have grabbed headlines over the past two years. 

"JDK 8 is in many ways the Lambda release at this point," IDC analyst Al Hilwa told ADTmag in an earlier interview. "It is always a concern when release dates slip, but under the circumstances the team is prioritizing the right work, namely a deeper security review.  Platform technology like Java are difficult to stabilize and a shift to a schedule-oriented release strategy may not be easy to adopt in the short term."

In addition to Project Lambda, Milestone 8 comes with a number of new features, including the new Date and Time API (JSR 310); Compact Profiles, which defines some subset Profiles of the Java SE platform to run on small devices; the Nashorn JavaScript Engine (JSR-223), which aims to allow Java developers to embed JavaScript in Java applications. Reinhold also noted the removal of Permanent Generation from the HotSpot virtual machine.

Reinhold encouraged the developer community to take Milestone 8 for a test drive.

"If you've been watching JDK 8 evolve from afar," he wrote, "then now is an excellent time to download a build and try it out -- the sooner the better! Let us know if your existing code doesn't compile and run correctly on JDK 8, if it runs slower than before, if it crashes the JVM, or if there are any remaining design issues in the new language and API features."

He added: "We'll do our best to read, evaluate, and act on all feedback received via the usual bug-reporting channel between now and the end of October. After that we'll gradually ramp down the rate of change in order to stabilize the code, so bugs reported later on might not get fixed in time for the GA release."

About the Author

John K. Waters is the editor in chief of a number of sites, with a focus on high-end development, AI and future tech. He's been writing about cutting-edge technologies and culture of Silicon Valley for more than two decades, and he's written more than a dozen books. He also co-scripted the documentary film Silicon Valley: A 100 Year Renaissance, which aired on PBS.  He can be reached at [email protected].