main.js

(function () {
  "use strict";

  // During development we direct STDOUT/STDERR from the backend app to a file
  var fs = require("fs");
  var out = fs.openSync("./out.log", "a");
  var err = fs.openSync("./out.log", "a");

  // The backend Java App is spawned to run in the background
  var spawn = require("child_process").spawn;
  var child = spawn(
    "java",
    ["-Dserver.port=8181", "-jar", __dirname + "/target/app.jar"],
    {
      detached: true,
      stdio: ["ignore", out, err],
    }
  );
  child.unref();

  var electron = require("electron");
  var app = electron.app; // Module to control application life.
  var BrowserWindow = electron.BrowserWindow; // Module to create native browser window.

  // Keep a global reference of the window object, if you don't, the window will
  // be closed automatically when the JavaScript object is garbage collected.
  var mainWindow;

  // Quit when all windows are closed.
  app.on("window-all-closed", function () {
    // On OS X it is common for applications and their menu bar
    // to stay active until the user quits explicitly with Cmd + Q
    if (process.platform != "darwin") {
      app.quit();
    }
  });

  // This method will be called when Electron has finished
  // initialization and is ready to create browser windows.
  app.on("ready", function () {
    // Create the browser window.
    mainWindow = new BrowserWindow({
      width: 1300,
      height: 700,
    });

    // and load the index.html of the app.
    mainWindow.loadFile("index.html");

    // Open the DevTools
    //mainWindow.webContents.openDevTools();

    // Emitted when the window is closed.
    mainWindow.on("closed", function () {
      // Dereference the window object, usually you would store windows
      // in an array if your app supports multi windows, this is the time
      // when you should delete the corresponding element.
      mainWindow = null;
    });
  });

  app.on("quit", function () {
    // Close and destroy the backend Java process
    child.kill("SIGINT");
  });
})();