Is Java installed? To run the Java command, first you must have Java installed. This means either the Java Runtime Environment (JRE) or the full Java Development Kit (JDK).

The Java Runtime Environment (JRE), also known as Java Runtime, is part of the Java Development Kit (JDK), a software development environment for writing Java applications.

I wrote a Java application that I'd like to run on any machine that has the appropriate Java Runtime Environment installed. I'm used to running apps via the SDK binaries, i.e. "java [application ...