JDK 8 Now Feature Complete
- Wrangling Actionable Insights from Organizational Data
- Cloud Information Technology: A Model for the Networked Company
- 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
In fact, it won't be until September of this year that we see the first developer preview that has passed a certain level of testing. The builds you download now are developer builds and are risky to use in terms of bugs, so be sure NOT to use them for production systems. However, they are good tools to use to get some exposure to the new features of JDK 8, which at this point revolves around Project Lambda. Here is a more complete list, if you're curious.
As for how I test Java developer builds, I create a virtual OS with VirtualBox (which is freely available here) and install the latest builds there to work with. This way, my mainstream Java developer environment isn't affected.