Please consult JMRI Setup Help.
JMRI® requires that Java be installed, whether your computer is Mac, Windows, or Linux based.
Version 2.12 can run on any computer system that will run Java 1.5 or later.
Version 2.14.1 requires Java 1.5 (or 1.6 if you wish for drag & drop)
Version 3.10.1 requires Java 1.7 or later.
Version 4.2 requires Java 1.8.
Full instructions for installing on different platforms can be found here: