Rhino is an open-source implementation of JavaScript written entirely
in Java. It is typically embedded into Java applications to provide
scripting to end users.

Rhino is an implementation of the core language only and doesn't contain
objects or methods for manipulating HTML documents.

Rhino contains

    * All the features of JavaScript 1.6
    * Allows direct scripting of Java
    * A JavaScript shell for executing JavaScript scripts
    * A JavaScript compiler to transform JavaScript source files
      into Java class files
    * A JavaScript debugger for scripts executed with Rhino

WWW: https://developer.mozilla.org/en-US/docs/Mozilla/Projects/Rhino