Java's Chief Architect, Mark Reinhold (Oracle) has proposed a delay to the Java 9 release schedule.
The current schedule has Java 9 being feature complete by 10th December this year, to allow for an approximate 9 month rampdown before general availability (GA) in September 2016. Under the new proposal, this timescale shifts back by 6 months. This means the new proposed feature complete date would become 25th May 2016, with GA moving to 23rd March 2017.
Reinhold's post to the OpenJDK 9 mailing list cites Project Jigsaw (the new modularity features of Java) as the primary reason for wanting to make this change. The proposal seems to reflect consensus that more time is needed to allow modularity to fully mature. Early access builds of JDK 9 that allow developers to begin exploring modularity have recently emerged, but widespread community testing is still just getting started. The tooling infrastructure for developing on modular JDKs is still quite experimental, and although all major IDEs and build tools are working on supporting Jigsaw, there is still a long way to go.
It seems very likely that the OpenJDK community will welcome this proposal. The changes to Java that modularity and Jigsaw bring are understood to be very large and complex, so there is no appetite for rushing to ship a substandard implementation. Stephen Colebourne (Java Champion, and spec lead for the admired Java 8 Date & Time API) remarked: "It will come as no surprise that I welcome the chance to get modules right, even if that means a delay".
Reinhold comments that: "It would be best to use the additional time to stabilize, polish, and fine-tune the features that we already have rather than add a bunch of new ones". This could be an excellent opportunity to fully test and derisk some of the other major changes, such as the standardization or removal of sun.misc.Unsafe and the change of default garbage collector which have met with a far more guarded community response than the core of Jigsaw itself.