Nashorn is Oracle's open source server-side JavaScript dialect. It has been supplied as part of the Java Runtime Environment (JRE) since version 8, meaning that everyone who installed Java 8 (or later) on a mainstream platform (Windows, macOS, and Linux, including Raspberry Pi) has a copy. It replaces Mozilla's Rhino, a JVM JavaScript dialect that was supplied with Oracle's implementation of Java Development Kit (JDK) versions 6 and 7.
Nashorn can be compared with Node.js, the popular server-side JavaScript platform that is powered by Google's V8 JavaScript engine. Both run JavaScript scripts on the server, in contrast to a client-side JavaScript engine that runs inside an internet browser. It's important to realize that Node.js and Nashorn scripts are not compatible with each other. This is because both Node.js and Nashorn add their own...