The JDK 8 Developer Preview (a.k.a. Milestone 8) builds are now available!

This milestone is intended for broad testing by developers. 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 aims to make it easier to write code for multicore processors. It adds lambda expressions, default methods, and method references to the Java programming language, and extends the libraries to support parallelizable operations upon streamed data.

There are, of course, many other new features, including a new Date and Time API (JSR 310), Compact Profiles, the Nashorn JavaScript Engine, and even some anti-features such as the removal of the Permanent Generation from the HotSpot virtual machine. A complete list of new features is available on the JDK 8 Features page.

If you’ve been watching JDK 8 evolve from afar 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.

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.