A sample Scala/JavaFX application

As a brief note to self, here’s an example JavaFX application written in Scala:

object MainWindow {
    def main(args: Array[String]) {
        Application.launch(classOf[MainWindow], args: _*)

class MainWindow extends Application  {
    override def start(stage: Stage) {
        val borderPane = new MainBorderPane
        val scene = new Scene(borderPane, 600, 400)
        stage.setTitle("Al’s Pizza")
How to start a Play Framework application running as a service on Ubuntu 16.04 alvin April 30, 2018 - 6:17pm

As a relatively brief note, this seems to be the correct way to start a Play Framework application as a service on an Ubuntu 16.04 system.

A shell script to start your Play application

First, you need to create a little Unix shell script that runs the startup command for your Play Framework application. I created a Play application for a website named, so I cd into the directory for that website:

Using Scala with Java Swing classes is pretty seamless

If you ever wanted to use Scala with Java Swing classes (like JFrame, JTextArea, JScrollPane, etc.), the process is pretty seamless. Here’s an example of a simple Scala/Swing application where I show a text area in a JFrame:

Android source code to show a popup dialog with a text field

I am working on a way to rapidly mock up Android applications using Android Studio, i.e., to rapidly prototype Android applications on the fly, and little snippets of code help to make this happen. For instance, this snippet of code shows how to show a popup dialog to prompt a user to enter information into a text field:

MacOS screen annotation/presentation software

I was going to write a little application to let me annotate my MacOS screen during presentations, but the Ink2Go product looks like it does exactly what I was thinking. As I’m creating a video presentation, such as when showing how to write some Scala or Android code, I want to be able to draw on the screen, such as writing text, arrows, circles, and boxes to highlight parts of the screen. Ink2Go looks like what I want.

Example: How to use javapackager to build a MacOS application bundle alvin August 15, 2017 - 6:18pm
Table of Contents1 - Building a MacOS application bundle with javapackager2 - The longer story3 - The Mac/Java class4 - The three scripts5 - javapackager notes

I recently learned how to use the Java javapackager command to build a macOS application bundle — i.e., a regular macOS application — from a Java application. In this tutorial I’ll show how to create a Mac application bundle from a simple Java class, in this case a Java Swing class.

MacOS/Java AppBundler error: NoSuchFileException: Info.plist

If you’re using the Oracle AppBundler to build a Mac/MacOS application bundle from a Java application and run into this error when running Ant:

NoSuchFileException: <directory path here> Info.plist

I have found that the problem is that I have not set and exported JAVA_HOME. To set and export JAVA_HOME on MacOS 10.12, I use this command in the shell script I use to build my Mac/Java app: