Single-file, persistent, sorted key-value store for Java (alternative to Berkeley DB) [closed]

Answer 1

You should definitely try JDBM2, it does what you want:

• Disk backed HashMaps/TreeMaps thus you can iterate through keys.
• Apache 2 license

In addition:

• Fast, very small footprint
• Transactional
• Standalone jar have only 145 KB.
• Simple usage
• Scales well up to 1e9 records
• Uses Java serialization, no ORM mapping

UPDATE

The project has now evolved into MapDB http://www.mapdb.org

Answer 2

Persistit is the new challenger. It's a fast, persistent and transactional Java B+Tree library.

I'm afraid that there's no guarantee that it will still be maintained. Akiban, the company supporting Persistit, was recently acquired by FoundationDB. The latter did not provide any information on the future.

https://github.com/akiban/persistit

Answer 3

H2 http://www.h2database.com/

It's a full-blown SQL/JDBC database, but it's lightweight and fast

Answer 4

I just would like to point out that the storage backend of H2 can also be used as a key-value storage engine if you do not need sql / jdbc:

http://www.h2database.com/html/mvstore.html

Answer 5

Take a look at LMDBJava, Java bindings to LMDB, the fastest sorted ACID key-value store out there.

Answer 6

It won't be a single file, but if you want embedded database, I suggest Java DB (a rebranded version of Apache Derby, which I used in a previous job with wonderful results).

Plus, both are completely free.

Edit: reading the other comments, another note: Java DB/Derby is 100% Java.