As you may know, support for Java 8 has been discontinued, and the current long-term support version is Java 11. Therefore, Erik Kemperman and I have been working to make the Power TAC system compatible with Java 11. As of today, the master branch on github for both powertac-core and powertac-server will not build with Java 8; you will need to migrate if you are working from source. In other words, if you pull changes from github and try to build, the build will fail unless you are using Java 11. If you upgrade to Java 11, everything should work, except that you will get a number of warning messages about illegal access. This is coming from the XStream library we're using to serialize the messages between server and broker in xml format. You can safely ignore these while we work to eliminate them.
We have not yet deployed the updated version to the Sonatype repo, so if you are using 1.7.0-SNAPSHOT rather than building the server from source, you won't see a change. We plan to delay a new deployment for several weeks to allow you to upgrade your systems.
Note that if you are using the STS/Eclipse setup for development, you may need to upgrade to the latest version for the Java 11 environment.
I have confirmed that a broker built under Java 8 appears to work correctly in the updated environment, so it should not be necessary to re-build existing brokers.
A big thanks to Erik for his careful work on this upgrade. It was not trivial.
If you've updated to Java 11 and would like to get rid of the error messages you get from maven 3.6.0 during a build, then it may be time to upgrade to maven 3.6.3. Most of the error messages you have been seeing will go away. If the maven upgrade is too complicated, then don't worry about it, the error messages seem harmless enough.
We plan to deploy the updated 1.7.0-SNAPSHOT the week of 9 December, and we plan to release 1.7.0 in late January or early February. These versions require Java 11, and the 2020 tournament will be run with 1.7.x. So it's time to get your Java environment updated and make sure you can run the updated server and that your broker works in this environment. If you encounter difficulties, please don't hesitate to ask for help.
Five minutes ago, I finished deploying the Java 11 upgrade to the Sonatype snapshot repo. So at this point, you will need Java 11 to run the system. This should also fix the problems a couple of you have had with a change in one of the junit library names in sample-broker, which I unfortunately committed in github before deploying the matching master pom in powertac-core that's part of the Java 11 upgrade. If this does not fix that problem, please let me know immediately.
As always, if you have problems, concerns, or questions, please don't hesitate to ask.