Looking for a drop-in replacement for a java.util.Map

Question

Problem

Following up on this question, it seems that a file- or disk-based Map implementation may be the right solution to the problems I mentioned there.

Answer 1

Berkeley DB Java Edition has a Collections API. Within that API, StoredMap in particular, is a drop-in replacement for a ConcurrentHashMap. You'll need to create the Environment and Database before creating the StoredMap, but the Collections tutorial should make that pretty easy.

Per your requirements, Berkeley DB is designed to be easy to use and I think that you'll find that it has exceptional scalability and performance. Berkeley DB is available under an open source license, it's persistent, platform independent and allows you to search for data. The data can certainly be purged/deleted, as needed. Berkeley DB has long list of other features which you may find highly useful to your application, especially as your requirements change and grow with the success of the application.

If you decide to use Berkeley DB Java Edition, please be sure to ask questions on the BDB JE Forum. There's an active developer community that's happy to help answer questions and resolve problems.