The manufacturing launch of Java Development Kit 12, based mostly on Java SE (Standard Edition) 12, is now out there. JDK 12 builds can be found from Oracle for Linux, Windows, and MacOS.
Where to obtain JDK 12
You can obtain the JDK 12 from the Java.internet web site.
Open supply builds are supplied below the GNU General Public License v2, with Classpath Exception. Commercial builds of JDK 12 from Oracle may be discovered on the Oracle Technology community below a non-open supply license.