Yup. I'm trying on my spare time (på ensamma hemmakvällar, if I may quote Dynamit-Harry) to get some sort of java running on AmigaOS4.
I'm using JAmiga 0.0.5 from sourceforge. I made some changes, but I can't remeber which ones right now.
However, as stated on amigans.net the crucial part is not the JVM, but the classpath. On the JAmiga site you can download a pre-compiled GNU classpath of version 0.5, or so, but we reallt want a later one. I downloaded classpath 0.98. I initially tried to compile it on OS4, but it seems I miss javac. I tried using kaffe, but it uses the ixemul library, and I didn't want that. A version on Aminet also crashed on me.
So, I tried crossompiling it on my Vista-machine with Cygwin and ZeroHeros cross-compile setup. I downloaded classpath 0.98 and did these steps:
1. Set the classpath to the classpath-0.98/-dir
2. Ran this:
./configure -C --disable-gtk-peer --disable-gconf-peer --disable-plugin --host=ppc-amigaos
And it didn't work. I couldn't compile Java.
I got tired, but found a link: http://developer.classpath.org/mediation/ClasspathOnCygwin