Create a First Application

Now that the purposes of the Sandboxed Applications have been explained, let’s create a first application.

A Sandboxed Application project can be created in the SDK with the menu File > New > Sandboxed Application Project.

Sandboxed Application Project Creation Menu

Sandboxed Application Project Creation Menu

The project creation window is displayed:

Sandboxed Application Project Creation Form

Sandboxed Application Project Creation Form

Once the Application information are fulfilled and validated, the project is created with the following structure:

Application Java sources;
Application resources (raw resources, images, fonts, nls);
Module description file, containing build information and dependencies of the project.

The next sections describe the required files to have your first basic Application.

Entry Point

A Sandboxed Application must contain a class implementing the ej.kf.FeatureEntryPoint interface in the src/main/java folder:

package com.mycompany;

import ej.kf.FeatureEntryPoint;

public class MyApplication implements FeatureEntryPoint {

    public void start() {
        System.out.println("Feature MyApplication started!");

    public void stop() {
        System.out.println("Feature MyApplication stopped!");

This class is the entry point of the Application. The method start is called when the Application is started. It is considered as the main method of the Sandboxed Application. The method stop is called when the Application is stopped. Please refer to the Sandboxed Application Lifecycle chapter to learn more about the Applications lifecycle.

The src/main/java folder is also the place to add all the other Java classes of the Application.


A Sandboxed Application project must contain a file with the .kf extension in the src/main/resources folder. This file contains the configuration of the Application. Here is an example:


It contains the following properties:

  • name: the name of the Application
  • entryPoint: the Full Qualified Name of the class implementing ej.kf.FeatureEntryPoint
  • types: this property defined the types included in the Application and must always be * (do not forget the space at the end)
  • version: the version of the Application

SSL Certificate

A Sandboxed Application requires a certificate for identification. It must be located in the src/main/resources folder of the project. The project created by the SDK provides a sample certificate. This certificate is sufficient for testing, but it is recommended to provide your own.

Module Descriptor

The module.ivy file is the Module description file which contains the project information and declares all the libraries required by the Application. See MicroEJ Module Manager for more information.

The dependencies must contain at least a module containing the ej.kf.FeatureEntryPoint class, for example the KF library:

<dependency org="ej.api" name="kf" rev="1.6.1" />