NativeJavaApp

Scaffold for creating double-clickable apps using Java

This project uses Apache Ant and JDK 25 to compile, bundle, and package a Java application into native installers (.dmg for macOS, .deb for Ubuntu, and .msi for Windows).

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Common Requirements (All Systems)

Before running the build, ensure the following are installed and configured:

• JDK 21 or 25: Must be installed. Although jpackage was introduced in JDK 14, JDK 21+ is recommended for modern macOS/Linux/Windows support.
• Apache Ant: Installed and available in your PATH.
• JAVA_HOME: This environment variable must point to your JDK installation directory.
  • Check via: ant -version and java -version

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macOS Setup

To build the .dmg installer, your Mac needs the following:

• Xcode Command Line Tools: Required for various build utilities.
  • Install via: xcode-select --install
• Icon Asset: A file named icon.icns must be in the project root.
• Note on Security: Since the app is not "Signed" with an Apple Developer Certificate, users may need to Right-Click > Open the app the first time to bypass the "Unidentified Developer" warning.

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Ubuntu / Debian Setup

To build the .deb package on Linux, jpackage requires external tools to create the Debian archive structure.

Run the following command to install the necessary packaging dependencies:

sudo apt update
sudo apt install ant fakeroot dpkg-dev

• fakeroot: Allows the package to be built with correct file permissions without requiring root access.
• dpkg-dev: Provides the core utilities to create Debian packages.
• Icon Asset: A file named icon.png (512x512 recommended) must be in the project root.

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Windows Setup

To build the .msi installer on Windows, ensure the following:

• JDK 21 or 25: Must be installed with JAVA_HOME configured.
• Apache Ant: Installed and available in your PATH.
• WiX Toolset: Required by jpackage to create MSI installers.
  • Download and install from: https://wixtoolset.org/releases/
  • Version 3.11 or higher is recommended.
  • After installation, verify WiX is in your PATH by running: candle -?
• Icon Asset: A file named icon.ico must be in the project root.
• Note on Security: Windows may show a SmartScreen warning for unsigned installers. Users will need to click "More info" > "Run anyway" to install the app.

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Project Directory Structure

Ensure your project looks like this for the build.xml to find all resources:

MyAppName/
├── src/
│   └── Main.java       # Your source code
├── icon.icns           # Required for macOS DMG
├── icon.png            # Required for Ubuntu DEB
├── icon.ico            # Required for Windows MSI
└── build.xml           # The Ant build script

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Usage Commands

Open a terminal in the project root and use the following targets:

Command	Description
ant	The default; runs the package target.
ant package	Automatically detects OS and builds .dmg (Mac), .deb (Linux), or .msi (Windows).
ant run	Compiles and launches the app immediately for testing.
ant clean	Deletes the build/ and dist/ folders to start fresh.
ant -p	Displays a help menu of all available targets.

Troubleshooting

"jpackage not found":	Ensure your JAVA_HOME is set to a JDK version 14 or higher. The jpackage binary resides in $JAVA_HOME/bin/.
Linux Icon Error:	If the Linux build fails, ensure icon.png is not just a renamed .icns or .jpg. It must be a valid PNG file.
Windows "candle.exe not found":	Install WiX Toolset 3.11+ and ensure it's in your PATH. jpackage uses WiX to create MSI installers on Windows.
Permissions:	If the generated .app or .deb won't execute, ensure you have the necessary write permissions in the dist/ directory.

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Automated Releases

This project uses GitHub Actions to automatically build and distribute native installers. The workflow is split into two phases: Build and Release.

The Build Phase (Continuous Integration)

Every time you push code to the main branch or open a Pull Request:

• GitHub starts a macOS runner, an Ubuntu runner, and a Windows runner.
• All systems compile the code and create their respective installers (.dmg, .deb, and .msi).
• The installers are saved as Artifacts in the GitHub Actions run summary for 90 days.

The Release Phase (Continuous Deployment)

A formal GitHub Release is only triggered when you push a version tag. This creates a permanent download page for users.

How to trigger a new release:

To release a new version (e.g., version 1.0.1), run the following commands in a terminal:

# 1. Tag the current commit
git tag v1.0.1

# 2. Push the tag to GitHub
git push origin v1.0.1

Downloading the Installers

• Go to the Releases section on the right-hand sidebar of this GitHub repository.
• Find the latest version (e.g., v1.0.1).
• Under Assets, you will find:
  • MyAntApp-Installer.dmg (for macOS)
  • MyAntApp-Linux.deb (for Ubuntu/Debian)
  • MyAntApp-Windows.msi (for Windows)

Changing the Version Number

When ready to bump the version, remember to update the version number in two places to keep everything in sync:

• The Git Tag (the v1.0.1 above).
• The app.version property at the top of build.xml. This ensures that when the user installs the app, the OS sees the correct version number in the "About" or "Get Info" screens.

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Native Java App Website

https://metrocs.github.io/NativeJavaApp/

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References

jpackage

• https://docs.oracle.com/en/java/javase/25/docs/specs/man/jpackage.html

Alternatives

• jDeploy: https://www.jdeploy.com