JBang Examples

GITHUB PROJECT: https://github.com/Pi4J/pi4j-jbang

Want to get started with Java programming on the Raspberry Pi?

JBang is a great way to create your first program to control electronic components connected to the GPIO pins. What is JBang?

What is JBang?

As described on their website:

JBang lets Students, Educators and Professional Developers create, edit and run self-contained source-only Java programs with unprecedented ease.

  • Want to learn, explore or use Java instantly without setup?
  • Do you like Java but use python, groovy, kotlin or similar languages for scripts, experimentation and exploration?
  • Ever wanted to just be able to run Java from anywhere without any or very minimal setup?
  • Ever tried out Java 11+ support for running .java files directly in your shell but felt it was a bit too cumbersome?

JBang lets you do all this!

Get Started with JBang on Raspberry Pi

Prerequisites

  • A Raspberry Pi with recent Raspberry Pi OS.
  • Install JBang as described on jbang.dev/download. JBang will install Java if it’s not installed yet.
# Install JBang
$ curl -Ls https://sh.jbang.dev | bash -s - app setup

# Check JBang by requesting its version
$ jbang --version        
0.109.0

# Install Visual Studio Code
$ sudo apt install code

Example scripts

The Pi4J JBang project on GitHub contains several examples to demonstrate both JBang and Pi4J. Each java-file is a full-containing runnable JBang application. This means you don’t need Maven, Gradle, or other Java build tool.

To tell JBang that it must handle the file as a Java application and do some upfront preparation work, the first line in each file is: ///usr/bin/env jbang "$0" "$@" ; exit $?.

When an application needs dependencies, they are defined inside the file itself in a line starting with //DEPS. For instance, to use the Pi4J Core library: //DEPS com.pi4j:pi4j-core:2.3.0.

Each of the provided examples contains more information about the wiring inside the file itself and are also explained here on the Pi4J website.

Get the Examples from GitHub

You can clone the project with the examples to your Raspberry Pi in the terminal with the following commands:

$ git clone https://github.com/Pi4J/pi4j-jbang
$ cd pi4j-jbang

Detailed Info of Each Example

The examples in the GitHub project are explained on these pages:

Video Demo

This approach to demonstrate Pi4J with JBang has been explained and demonstrated on Voxxed Days Brussels on May 23th, 2023.