I would just like to ask if this information would be useful for the public:
On Ubuntu 16.04.2, the openjdk-9-java-amd64 via the repository does not have javac. Using openjdk-9-java-amd64 (as exposed via the toolchain-sample-linux.xml file) will result in failure, at least with sudo apt-get install on the latest Ubuntu. Only after installing and configuring the oracle version of the jdk-9 early access will builds of the log4j2-api-java9 build correctly. After discovering the --release flag is a new feature to java 9 I able to hunt down the problem. I'd like to save others the frustration of my experience. Thanks to Matt and Ralph and others who offered their help and expertise in helping me track down a fix. Kenneth
