Oracle released Java 12 last week, and the new release can now be installed in Ubuntu, Linux Mint and Debian from the Linux Uprising Java PPA. The new version will receive a minimum of 2 updates, and it will followed by Oracle JDK 13 in September 2019.
The release announcement contains information about Oracle Java 12, including what's new.
Like previously mentioned, Oracle uses a new commercial license for Java starting with Java 11, so you should use OpenJDK when possible. From Java 11 forward, Oracle JDK builds and OpenJDK builds are essentially identical with a few differences you can read about here.