Java EE (Java Enterprise Edition) General Discussion

I'm running xjc.exe on a Windows XP machine via a .bat file to generated the binding Java files for my .xsd file. JDK 1.6.0_16 is installed. The bat file looks like this:

xjc.exe -p my.packagepath xsdfile.xsd

Those aren't really the file and package names I'm using but you get the point. i run the .bat file and it runs without any error. It happily and without complaint generates a couple .java files in the my\packagepath directory. But that's it. There is no impl sub-directory being created at all. I've used JAXB on a project like this a couple years back and I see that the impl directory and a runtime folder with several more auto-generated files is there for that project. But it doesn't seem to be working now and I've forgotten how I got it to work last time. What am I missing or forgetting to do?