Java on a Mac consists of two primary software components: An internet plug-in used to run Java macOS 10.14 - Java SE v11 (but Java web browser plug-in not supported in Safari v12 or later). Java v9 has been replaced with Java v11 (April 2018 saw the start of the new version numbering.
Java 11 The implementations of Java 8, 9, 10, and 11 based on from vendors such as, and run on macOS High Sierra and Mojave (and some older macOS as well). Java 12, not yet released for production, runs on High Sierra as well.
LTS Note that some versions of Java are designated for Long-Term Support (LTS). Versions 8 and 11 are both LTS.
This means the version will receive updates and fixes for years instead of months. This applies, at least, customers paying a commercial vendor. Free-of-cost implementations may also receive updates under LTS from some providers. We’ve yet to see if that happens or not. This approach using rapid delivery train with LTS is new in the Java world.