Apparently JPL started shipping with the Perl distribution as of 5.005_54 or somesuch release (according to this press release). So if you have a recent release, you may have the JPL stuff. Take a look at the results on search.cpan.org.

As for how to use it... well, I've really no idea. :)

Why do you want to use Java for your network code, incidentally? Rather than Perl's socket support, I mean.