If you're looking to convert this company back to Perl, don't bother. They've already got a working solution, and there's no point in undoing all the hard work again just so your favorite language can be used instead.

If you're looking for defenses against PHB's who look at this and try to force their own departments to switch, consider what perrin said. This company almost certainly wasn't using mod_perl or FastCGI or some other embeded interpreter, whereas they almost certainly were doing the equivilent for Java.

For a fair comparison, one only needs to write a "Hello, World!" in both languages, compile the Java program, and run them both. The Perl program will be done long before the JVM even finishes loading.

That test is mostly irrelevent, since nobody actually runs a Java-based web app like that (nobody sane, anyway). Similar to mod_perl, Java servlets have their JVM built into the web server, so JVM startup time can be ignored. Naturally, the same goes for Perl code running on a web server with mod_perl.

I strongly suspect that the company in question is making an unfair comparison. Ask them to convert all their servlets to Java CGIs and see how fast they run :)