No JavaScript, no CSS, no obscure Annotations, just plain Java... That alone does surely catch my attention...
Increase the reach of your offer
Try to participate in University events. At my University there was a week where Companies would come to the campus and give speeches about what they did and why they were a good working option. Then they would gladly collect CV's of interested students. You may even receive a paid grant to get to know each other from the inside.
Catch their attention
Nowadays there's more frameworks than programmers and it's cool of you're using the latest framework which saves you from typing a semicolon at the end of each line...
So, why would a programmer be attracted to an old technology stack? No JavaScript, No CSS, just Java would be a good enough catch phrase for me (not related to any film).
Salary is one that's already been mentioned. What about pride? This job is not suited for everyone, you need to be a capable developer because you can't simply browse SO for the solution... Maybe this job offers intellectual challenges that will make you love it.
When you post a job offer on the Internet, give the feeling that the company is not dinosaurs with computers (I'm sorry, but it's the first thing that comes to my mind when I read COBOL). Are there any activities your workers perform that the attendees may join if they're hired? Laser games, maybe?
Does the job offer allow you to work some days a week from home after the onboard stage?
Keep them interested in your offer
For some people salary may not be what catches their attention, but something that keeps them interested. Another typical one is training: I highly appreciate jobs that sponsor official (out of the company) certificates.
If technologies are uncommon or rare, your candidates may want some job stability. Do you offer a long-term contract? Also, what are the chances of internal promotion?
