Compiling Java applications to native Windows executables

Being a Java developer really sucks when it comes to making end-user desktop applications. You want these applications to be light, fast and easily redistributable. Packaging a bunch of jars along with startup script is the worst thing you can do. It may work quite well in various Linux distributions, where you can make a .deb or .rpm which automatically installs JRE, puts startup script to /usr/local/bin and creates a nice launcher with icon in the applications menu. In Mac OS you can use that outdated JRE that comes by default and then easily bundle all scripts and jars into an .app. But in Windows it does not work that way. You can use JSmooth to make .exe out of .jar and use NSIS to create a nice installer, but there still is a problem. User may not have a compatible JRE, or he/she may choose not to have one just because Java sucks for running on it's bloated memory hogging virtual machine. I have to agree here. As a user, I have no faith in desktop applications that are written in Java.

So what is the solution? Compile to native executable and forget JRE. It is possible, but it will not be a walk in the park. First, you will have to get familiar with GNU Compiler Collection and particularly with GCJ.

Let's compile a Hello World application like this one:

public class Hello {
    public static void main(String[] args) {
        System.out.println("Hello native world!");
    }
}

1. Get the patched GCJ here: http://www.thisiscool.com/gcc_mingw.htm (120 MB)
2. Extract it somewhere and add thisiscool-gcc/gcc-ejc/bin to your PATH
3. Compile Hello.java as Hello.exe: gcj --main=Hello -o Hello Hello.java
4. Enjoy your statically linked Hello.exe which prints Hello native world! and runs without JRE.

Wait. Hello.exe is 37MB? Holy crap! Well, it's a little overhead you have to pay for loosing the JRE, this .exe contains the whole garbage collection mechanism, etc. Also, you will be able to compile SWT GUI applications! It is possible to get smaller executables with MinGW tooling. Hello.java compiled with MinGW is about 3MB, but it has other issues, I couldn't manage to get the system output working. You may be more lucky though.

Anyway, when you compile native binaries, your Java code cannot be decompiled, so you have better protection than by using obfuscators. And the best thing is that end users won't complain that "it's crap because it's Java". They just wouldn't know.

I wish Sun (I just can't say Oracle when referring to Java, it makes me sick, sorry) could create an official AOT Java compiler so developers would not have to go through hellfire to make native executables.