It looks like for Perl you already know the components of your system, and can probably provide rought estimates on the time it's going to take to complete the project.

For this exact application Java doesn't offer any unique advantages over Perl. Management should evaluate the speed of development, and whether it's wise to switch to a new environment, when you've already assembled a team proficient in a different environment.

However, let me point that I think Java allows for better code reusability than Perl, and if you expect similar projects to pop up, it might be worth switching, but at the same time Perl is not terrible with reusability either.