Development has started on JDK 9: http://openjdk.java.net/projects/jdk9/. This issue is a place to track improvements needed for building/testing on JDK 9.
Test failures with JDK 9-ea b111
Make it possible to run Derby tests on early access versions of JDK 9
Support JDBC changes introduced by Java 9
Enable JDBC 4.2 tests on Java 9 and higher
Make it possible to build Derby using JDK 9