Java JAR wrapper for creating Windows native executables
created by LoRd_MuldeR <mulder2@gmx.de>

Introduction

Launch5j is a reimagination of “Launch4j”, with full Unicode support. This is a tool for wrapping Java applications distributed as JARs in lightweight Windows native executables. The executable can be configured to search for a certain JRE version or use a bundled one. The wrapper also provides better user experience through an application icon, a native pre-JRE splash screen, and a Java download page in case the appropriate JRE cannot be found.

Usage

There currently are two different ways to use Launch5j with your application code:

• Use the launcher executable with a separate JAR file

  Simply put the launcher executable (launch5j.exe) and your JAR file into the same directory. Launch5j will automatically detect the path of the JAR file based on the location of the executable file. More specifically, Launch5j detects the full path of the executable file and then replaces the .exe file extension with a .jar file extension. Of course, you can rename the launch5j.exe executable to whatever you prefer.

• Combine the launcher executable and the JAR file (“wrapping”)

  In order to combine the launcher executable (launch5j_wrapped.exe) and the JAR file to a single file, you can simply concatenate these files. The executable launcher must go before the JAR file content. There are many ways to achieve this, but one method is by running the following copy command-line in the terminal:

  copy /B launch5j_wrapped.exe + my_program.jar my_program.exe
  

  If you are building you application with Apache Ant, consider using the concat task like this:

  <concat destfile="my_program.exe" binary="true">
     <fileset file="launch5j_wrapped.exe"/>
     <fileset file="my_program.jar"/>
  </concat>
  

  The resulting my_program.exe will be fully self-contained and is the only file you'll need to ship.

  Warning: Code signing, as with Microsoft®'s SignTool, probably does not work with the “wrapped” executable file! If code signing is a requirement, please use a separate JAR file and just sing the launcher executable.

Variants

Launch5j executables come in a number of variants, allowing you to pick the most suitable one for you project:

• wrapped
  Expects that the JAR file and the executable launcher have been combined to a single file; default variant expects that a separate JAR file is present in the same directory where the executable launcher resides.

• registry
  Tries to automatically detect the install path of the JRE from the Windows registry; default variant expects the JRE to be located in the /runtime path relative to the location of the executable launcher.

• java<N>
  When detecting the JRE install path from the Windows registry, accepts only JRE version N.0 or any newer JRE version; default variant accepts only JRE version 8.0 (1.8.0) or any newer JRE version.

• only[32|64]bit
  When detecting the JRE install path from the Windows registry, accepts only 32-Bit (x86) or only 64-Bit (x64) JRE versions, respectively; default variant accepts 32-Bit and 64-Bit versions with a preference to 64-Bit.

• nowait
  Does not keep the launcher executable alive while the application is running; default variant keeps the launcher executable alive until the application terminates and then forwards the application's exit code.

• nosplash
  Does not display a splash screen while the application is launching; default variant does display a splash screen while the application is launching – will be hidden as soon as application window shows up.

Platforms

All of the above Launch5j variants are available as i586 (32-Bit) and x86-64 (64-Bit) executables. The i586 (32-Bit) executables can run on 32-Bit and 64-Bit versions of Microsoft® Windows™, whereas the x86-64 (64-Bit) executables require a 64-Bit version of Microsoft® Windows™. Consequently, it is generally recommended to distribute the i586 (32-Bit) launcher executable. Please note that this does not restrict the “bitness” of the JRE that can be used. Even the i586 (32-Bit) launcher executable is perfectly able to detect and launch a 64-Bit JRE – if it is available.

Note: Launch5j has been tested to work correctly on Windows XP (Service Pack 2), or a compatible newer version.

Customizations

Launch5j comes with a default executable icon and a default splash screen bitmap. These just server as an example and you probably want to replace them with your own application-specific graphics.

It is not necessary to re-build the executable files for that purpose. Instead, you can simply use a resource editor, such as XN Resource Editor or Resource Hacker™, to modify the pre-compiled executable files as needed:

Additional options

Some options can be configured via the launcher executable's STRINGTABLE resource:

• ID_STR_HEADING (#1)
  Specifies a custom application description that will be used, for example, as title of message boxes.

• ID_STR_JVMARGS (#2)
  Specifies additional options JVM options to be passed, e.g. -Xmx2g or -Dproperty=value.
  See here for a list of available options:
  https://docs.oracle.com/javase/7/docs/technotes/tools/windows/java.html

• ID_STR_CMDARGS (#3)
  Specifies additional (fixed) command-line options to be passed to the application.

Note: The default value "?" is synonymous with “undefined”, because resource strings cannot be empty!

Build instructions

In order to build Launch5j from the sources, it is recommended to use the GNU C Compiler (GCC) for Windows, as provided by the Mingw-w64 project. Other C compilers may work, but are not officially supported.

Probably the most simple way to set up the required build environment is by installing the MSYS2 distribution, which includes GCC (Mingw-w64) as well as all the required build tools, such as Bash and GNU make.

Please make sure that the essential development tools and the MinGW-w64 toolchains are installed:

$ pacman -S base-devel
$ pacman -S mingw-w64-i686-toolchain mingw-w64-x86_64-toolchain

Once the build environment has been set up, just run the provided Makefile:

$ cd /path/to/launch5j
$ make

Note: In order to create 32-Bit or 64-Bit binaries, use the mingw32 or mingw64 sub-system of MSYS2, respectively.

Acknowledgment

This project is partly inspired by the “Launch4j” project, even though it has been re-written from scratch:
https://sourceforge.net/p/launch4j/

License

This work has been released under the MIT license:

Copyright 2020 LoRd_MuldeR <mulder2@gmx.de>

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