Oracle has made available a preview of the development kit for Java SE (Standard Edition) 8 so that devs can try it out and iron out the bugs.

Java 8 isn’t due for release until next year, but in a blog post, Mark Reinhold, Chief Architect of the Java Platform Group at Oracle, says that the developer preview is available, and says:

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 new version includes Project Lambda, which is designed to support programming in a multicore environment by adding closures and related features to the Java language. Project Lambda is so important that, as we reported back in June, JDK 8 has been held up by the need to include features from it. Reinhold reports that this version adds lambda expressions with closures, default methods, and method references to the Java programming language, and extends the libraries to support parallelizable operations on streamed data. See Maurice Naftalin's Lambda FAQ for a good description of Project Lambda and why it’s important.

JDK 8 was originally slated for release this month, but the schedule was lengthened in April because of a renewed focus on security.

Alongside Project Lambda, JDK 8 has a new date and time API with better formatting and parsing. Compact profiles are now supported. These let applications that use just part of the Java SE platform specify which parts they need so they can run on resource-constrained devices.

The Nashorn JavaScript Engine is included, adding a lightweight high-performance JavaScript runtime in Java with a native JVM. This is intended to let you embed JavaScript in Java applications via JSR-223 and to develop free standing JavaScript applications using the jrunscript command-line tool.

As well as the additions, Reinhold says the new version has "anti-features" such as removal of the permanent generation from the HotSpot virtual machine. This will move part of the contents of the permanent generation in Hotspot to the Java heap and the remainder to native memory, so freeing space in native memory for class meta-data. See this list of JDK 8 Features for details of other improvements.

Reinhold says developers have till the end of October to report bugs and problems, saying:

“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.”