Best way to "prime" OpenJPA before first request?

[KARR, DAVID (ATTCINW)]

I'm building a REST-based app using CXF and OpenJPA 1.2.1.  The app
works fine, but I've noticed that the first request to the app after
startup takes quite a while, and most of the time is spent on the first
JPA request.  Following requests, even for different objects and
classes, goes much faster.  What are my possible options for "priming"
JPA at startup so that the first request doesn't take so long?