JDK 8 reached General Availability on 18 March 2013. Production-ready binary distributions based on the JDK 8 code base are available now from Oracle and will be available soon in most Linux distributions.
Development of JDK 8 Update Releases is being done in the nearby JDK 8 Updates Project.
JDK 8 was the second part of "Plan B". The single driving feature of the release was Project Lambda. (Project Jigsaw was initially proposed for this release but later dropped). Additional features proposed via the JEP Process were included so long as they fit into the overall schedule required for Lambda. Detailed information on the features included in the release can be found on the features page.
The original schedule aimed to ship the release in early September 2013, but due to an increased focus on browser-related security issues that date was not achievable. The final schedule, proposed on 2013/4/18 and adopted on 2013/4/26, was as follows:
2012/04/26 M1 2012/06/14 M2 2012/08/02 M3 2012/09/13 M4 2012/11/29 M5 2013/01/31 M6 2013/06/13 M7 Feature Complete 2013/09/05 M8 Developer Preview 2014/01/23 M9 Final Release Candidate 2014/03/18 GA General Availability
Further information on milestone content and the final phases of the release can be found on the milestones page.