Getting Started


The JavaScript runtime is currently in preview and is available as a demonstration bundle on demand. Please contact our support team.

Before going further with this getting started, follow the steps described in the README.rst of the demonstration bundle.

Let’s walk through the steps required to use Javascript in your MicroEJ application:

mmm init -Dskeleton.module=firmware-singleapp -Dskeleton.rev=1.1.12 -Dproject.module=myproject -Dproject.rev=1.0.0

Adapt the properties values to your need. See the MMM CLI init command documentation for more details.

Javascript is supported in the following Module Natures page: - Add-On Library, - Standalone Application, - Sandboxed Application.

  • add the js dependency in the module.ivy file:
<dependency org="com.microej.library.runtime" name="js" rev="0.10.0"/>
  • add the following lines in your application main class:
import com.microej.js.JsErrorWrapper;
import com.microej.js.JsCode;
import com.microej.js.JsRuntime;


  • create a file named hello.js in the folder src/main/js with the following content:
function hello() {
    var message = "MicroEJ Javascript application!";
    print("My first", message);

  • follow the steps described in the run command documentation
  • in a terminal, go to the folder containing the module.ivy file and build the project with the command:
mmm build

You should see the following message at the end of the build:


Total time: 20 seconds
  • now that your application is built, you can run it in the simulator with the command:
mmm run

You should see the following output:

My first  MicroEJ Javascript application!

You can now go further by exploring the capabilities of the MicroEJ Javascript engine and discovering the commands available in the CLI.