In a recent communication, Mark Reinhold, chief architect of the Java Platform Group at Oracle, suggested delaying the general availability of Java 9 by six months, to provide more time to finish Project Jigsaw. After some deliberation the delay was accepted, setting the general availability of Java 9 to March 2017, exactly three years after the release of Java 8.
Mark Reinhold has previously talked about the conflict of features vs. schedule, manifesting a preference towards keeping a relatively fixed schedule even at the expense of deferring features to a later release. He has, however, argued in favour of exceptions when the feature in question is considered the flagship feature of the newer version. For Java 9 the flagship feature is Project Jigsaw, so given the fact that it would slip the initial schedule, and considering it has seen reasonable progress in recent months, the community accepted the delay.
This decision aligned with a similar one that was taken for Java 8. When it became apparent that Java 8's flaghip feature Project Lambda wouldn't be ready on schedule, a delay was also proposed and accepted.
Project Jigsaw was originally scheduled for release in Java 8, but in 2013 Reinhold announced it would be deferred to Java 9 rather than hold up that release, and announced a two year cadence for future Java releases and accordingly a March 2016 release of Java 9. Then last May Reinhold set the official schedule GA date as September 2016, also a six month delay. If Reinhold's latest schedule holds, Java 9's release will be a full three years after the prior release.
Java 10 has not been scheduled but the flagship feature is expected to be Project Valhalla, who's goal is to provide advanced Java VM and language features such as value types, generic specialization, and enhanced volatiles.