We present Graal.JS, a JavaScript engine implemented in Java, compatible to the ECMAScript 262 Version 6 standard. Graal.JS is executed on top of the Graal VM (http://openjdk.java.net/projects/graal/). The Graal Java compiler ensures high performant execution of the JavaScript applications. The engine offers support for parallel execution of JavaScript functions via a dedicated API and runtime support. Additionally, it supports interoperability with Java, and other languages based on Truffle like Ruby, Python, or R. The session will give an overview of the architecture of the Graal.JS and include example applications running on top of the system, e.g. applications from the Node.JS ecosystem accessing databases in an optimised way.