Enhanced JEP 392: Packaging Tool

JEP 392: Packaging Tool is a significant enhancement introduced in Java 17 that provides a simpler, more streamlined way to package Java applications into platform-specific executables. This tool aims to ease the process of deploying Java applications by allowing developers to package their applications with native installers or executables, thereby eliminating the need for users to manually install the Java Runtime Environment (JRE) to run the application.

Key Features of JEP 392: Packaging Tool

The Packaging Tool introduced in JEP 392 allows developers to package Java applications (including their dependencies) into native images, ensuring that users don’t need to have a separate Java runtime installed. This is especially useful for distributing Java applications on various platforms like Windows, macOS, and Linux.

Key improvements and features include:

Native Package Creation:

• The Packaging Tool allows developers to package Java applications as native executables for various platforms (Windows, macOS, and Linux).
• The tool supports creating platform-specific installers and launchers, such as .exe files for Windows and .app bundles for macOS, making Java applications behave more like native applications.

Simplified Deployment:

• The Packaging Tool eliminates the need for Java end-users to install a separate JRE or JDK. The packaged application includes the necessary runtime along with the application code and resources.
• The tool handles packaging, bundling, and deploying Java applications, ensuring that all dependencies, resources, and configuration files are bundled in the final distribution package.

Cross-Platform Support:

• Developers can use the Packaging Tool to create platform-specific packages on any operating system. For example, developers on Linux can package a Java application as a .dmg for macOS or .exe for Windows.
• This cross-platform support ensures that developers can easily create packages for multiple platforms without requiring additional platform-specific tools.

Integration with JDK:

• The tool integrates seamlessly with the JDK and provides an easy-to-use interface for building platform-specific packages directly from the command line.
• It supports integration with existing build systems (such as Maven, Gradle, or custom build scripts), allowing developers to automate the packaging process as part of their regular build pipeline.

Minimal Packaging with Java Runtime:

• The tool enables the inclusion of the Java Runtime Environment (JRE) into the packaged application. This results in a much smaller, optimized runtime that only includes the components necessary to run the specific application, reducing the size of the distribution package.
• This leads to smaller package sizes compared to traditional distributions, making the packaged application more efficient and faster to download and install.

Command Line Interface (CLI):

The Packaging Tool is primarily driven from the command line, providing flexibility for developers to invoke it in various environments (e.g., CI/CD pipelines).

The tool uses a simple syntax to package applications with options for specifying the main class, destination directory, platform-specific configurations, and packaging formats.

Benefits of JEP 392: Packaging Tool

• Simplified Distribution: The tool allows for easy packaging of Java applications into native executables or installers, simplifying distribution. End-users can run the application without needing to install a separate Java runtime.

• Cross-Platform Compatibility: Developers can package their applications for multiple platforms, ensuring that the same Java application can run on Windows, macOS, and Linux without requiring specific platform-dependent modifications.
• Improved End-User Experience: By packaging Java applications as native executables, users can interact with them just like any other desktop application. They don’t need to deal with complex setup processes or managing Java installations.
• Smaller Application Size: The ability to include only the necessary components of the Java runtime reduces the size of the packaged application compared to full JDK distributions, making it more efficient for users to download and install.
• Automation: The Packaging Tool can be integrated into automated build systems like Maven or Gradle, enabling seamless automation of packaging during the build and release cycle.

Example: Using the Packaging Tool

To package a simple Java application using the Packaging Tool in Java 17, you can use the following command-line steps. For this example, let’s assume you want to package a Java application into a .pkg installer for macOS.

Step 1: Compile the Java Application

First, compile the Java application using the javac command:

javac MyApplication.javaCode language: CSS (css)

Step 2: Package the Application

Next, you can use the jpackage tool to create the native package. The jpackage command will bundle your Java application into a platform-specific package:

jpackage --input . --name MyApplication --main-class MyApplication --type pkg --destination ./output
Code language: JavaScript (javascript)