Packr
Packages Java applications (JAR, assets, and a JVM) into native executables for Windows, Linux, and macOS distribution.
What is Packr?
Packr is a packaging tool that bundles Java applications—including JAR files, assets, and a Java Runtime Environment (JRE)—into native executables for Windows, Linux, and macOS. It solves the problem of distributing Java apps by making them appear and launch like native applications, eliminating the need for end-users to install Java separately. This is particularly valuable for GUI applications like games, where a seamless user experience is critical.
Java developers building desktop applications, especially game developers using frameworks like libGDX, who need to distribute their software as user-friendly, native-like packages across multiple operating systems.
Developers choose Packr for its simplicity, cross-platform support, and ability to create self-contained executables that reduce user friction. Unlike some alternatives, it offers fine-grained control over JRE minimization and supports modern JVM features like the Z Garbage Collector, making it a lightweight and flexible solution for Java app distribution.
Overview
Packages your JAR, assets and a JVM for distribution on Windows, Linux and Mac OS X
Use Cases
Best For
- Packaging libGDX games for distribution on desktop platforms
- Creating native executables for Java-based GUI applications
- Reducing Java application bundle size via JRE minimization
- Distributing Java apps to users without a pre-installed JVM
- Cross-platform deployment of desktop software from a single codebase
- Bundling Java 14+ applications with Z Garbage Collector support
Not Ideal For
- Projects requiring automated notarization and code signing for macOS distribution
- Teams using Java 11+ who want integrated JRE minimization via jlink instead of custom profiles
- Applications needing self-updating packages or cross-building from a single operating system
Pros & Cons
Pros
Generates platform-specific launchers (.exe, binary, .app) that hide JVM startup, making Java apps appear native without user intervention, as shown in the usage examples.
Allows bundling a JRE with minimization profiles to reduce size, and supports removing non-matching native libraries from JARs, giving developers fine-grained control over distribution size.
Targets Windows, Linux, and macOS with a single configuration, enabling consistent packaging for desktop applications across major operating systems.
Supports Java 14+ and the Z Garbage Collector for low-pause GC, with automatic OS detection via --useZgcIfSupportedOs, enhancing performance for GUI apps.
Cons
JRE minimization is conservative and only effective for Java 8 or lower; for Java 11+, the README recommends using jlink instead, adding complexity for modern projects.
Requires manual steps for setting icons on Windows and Linux, and for macOS notarization and signing, which can be time-consuming and error-prone.
Only Adopt OpenJDKs 8, 11, and 15 are tested, and features like cross-building or advanced security are not built-in, relying on external tools or manual intervention.
Frequently Asked Questions
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