So schreibt Mark Reinhold unter http://mail.openjdk.java.net/pipermail/jdk9-dev/2017-January/005505.html:
We achieved the Feature Extension Complete milestone  in late December. All JEPs and small enhancements granted extensions  have been integrated into the JDK 9 master forest. Thanks to everyone for all your hard work leading up to this milestone! We're now in the first phase of the rampdown process, in which we aim to fix the bugs that need to be fixed and understand why we're not going to fix some bugs that perhaps ought to be fixed. We'll use the process that I previously proposed , which is now also documented under the JDK 9 Project page . The overall feature set is, at this point, frozen. It's highly unlikely that any further JEPs will be targeted to the release. Small enhancements to new features will be considered, but the bar is now much higher. Please request approval for such enhancements via the existing FC-extension process . Low-risk enhancements that add small bits of missing functionality or improve usability may be approved, especially when justified by developer feedback. Enhancements that add significant new functionality will require very strong justification. Enhancements to tests or documentation do not require advance approval.