Cache System Supporting Java Integration

Am building a restful web service which needs to populate data (from a parsed JSON object) into a cache.

Question(s):

1. What are the cheapest (preferably open source) and easiest to use cache systems that support Java, Web Service (Restful), and tomcat integration?

2. Do they have an expiration policy?

3. Do they have support for in-memory and / or file system persistence?

I am seeking something that doesn't require a big learning curve.

Thank you for taking the time to read this...

It says one reply for this post: Today 14:48:49 by William P O'Sullivan

But the only thing I see is some type of advertisement stating:

"I agree. Here's the link: jrebel"

Perhaps the response by Mr. Sullivan was deleted?