Rolling release of (usually) STSs OpenJDK OpenJDK has release cadence of 6 months, but 3/4 of them are Short Term Supported for 6 months only. This package is designed to harbor them. Currently it is build of OpenJDK 12. LTSs will go also as separate packages.
JDK12 is current release of Java platform. It is bringing many cool improvements - https://openjdk.java.net/projects/jdk/12/ and is landing to your Fedora. Where it will be maintained for f28 and newer. Unluckily, this package is STS (short term support) version. Between individual LTS there will be always several STS. Again, please see announcement: http://mail.openjdk.java.net/pipermail/discuss/2017-September/004281.html and See java SIG plans: https://jvanek.fedorapeople.org/devconf/2018/changesInjavaReleaseProcess.pdf . So this is rolling release of all STSs to come. Its fate during the release of fresh LTS is yet to be decided. You will always be allowed to install LTS in fedora build root, alongside with latest STS via alternatives.
See announcement: http://mail.openjdk.java.net/pipermail/discuss/2017-September/004281.html See java SIG plans: https://jvanek.fedorapeople.org/devconf/2018/changesInjavaReleaseProcess.pdf