JDK 8 has reached its feature complete milestone, though in fact some features were still not quite completed.

Milestone 7 is supposed to be the marker showing when the JDK 8 development schedule has reached the stage where all the features and unit tests have been implemented and integrated into the build. It is the final milestone before the developer preview. In all 22 JEPs were scheduled for M7, including five that were only added at the beginning of May. The full list is included on the Milestones schedule.

The development team decided to mark Milestone 7 even though three JEPs (JDK Enhancement Proposal) were still not completed. Two of the missing JEPs are related to improving security, while the third involves concurrency updates. All three were expected to be completed by build b93 which was scheduled for June 6. Mark Reinhold, Chief Architect of the Java Platform Group, said that future milestones should not be delayed by the holdup on this Feature Complete Milestone.

As we reported in February, JDK 8 has been held up by the need to include features from Project Lambda, and all the JEPs relating to this have now been completed.

The lambda support is needed for several platform goals, according to the details about its JEP which says that:

“The primary features of lambda expressions and virtual extension methods, along with their set of secondary supporting features, further several platform goals:

• Simplifying the creation and consumption of more abstract, higher-performance libraries
• Supporting smoother library evolution with migration compatibility”

Besides adding a now-common feature to the Java programming language, lambda expressions open up possibilities for improved multicore support by enabling internal iteration idioms.

The supporting language features around lambda include virtual extension methods, which will allow interfaces to be evolved in a source and binary compatible fashion.

The schedule was lengthened further in April because of a renewed focus on security and the new timetable for the remaining  three Milestones is:

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