I am currently looking into packaging jpox for Gentoo Linux. I experienced some initial problems compiling from source.

I first attempted to use maven. This failed immediately because it couldn't find ../project.xml. It turns out that the project.xml had this line:
<extend>${basedir}/../project.xml</extend>

And of course, this file didn't existed. I removed this line, and was able to continue on. I don't have access to the sun jars at the moment, so I can't comment on if there are any problems after that point.

Next I tried to use ant. Just running ant gives the error:
/local/users/jnichols/jpox/jpox-1.1.0-beta-6/build.xml:100: The following error occurred while executing this line:
Target `${build.setting.default.target}' does not exist in this project.

This made me suspect that some properties files were missing, and sure enough, there are several loaded at the top of build.xml, but none of them were present. Since it didn't know what to run by default, I tried running 'ant jar'. This failed with:
/local/users/jnichols/jpox/jpox-1.1.0-beta-6/build.xml:1304: java.net.MalformedURLException: no protocol: ${dependency.ant.url}

... which confirms to me that there the source tarball is missing some properties files.