Using gcj under gentoo

If you follow the instructions off of gentoo's website (they are very good instructions) for x86 on 2004.1 then you end up with a system that doesn't have gcj. Here's what I did to get it working.

This takes a while to run. I suggest starting the emerge under "screen". Type screen to start screen and then follow these instructions. If you don't have screen, type emerge screen. If you don't know what screen is see this post, number 6 on the list.

First, emerge gcc again like this:

USE="java gcj" emerge gcc

At the time, this emerged 3.3.2-r5

sys-devel/gcc
      Latest version available: 3.3.2-r5
      Latest version installed: 3.3.2-r5

Then create your little java app:

user@server /tmp $ cat HelloWorld.java
public class HelloWorld {
    public static void main(String args[]) {
        System.out.println("hi");
    }
}

Next, compile it like this:

gcj --main=HelloWorld -o Hello HelloWorld.java

Finally, run it:

user@server /tmp $ ./Hello
hi

Then you can move that file to another Linux box (provided all the libc libraries match and other stuff I don't know about) and run it. Very cool.

More info here: Linux Journal GCJ FAQ