Looking for a lightweight java-compatible in-memory key-value store

Question

Berkeley DB would be the best choice probably but I can't use it due to licensing issues.

Are there any alternatives?

@Stephen C: you are welcome to edit and provide better explanation. About "responding sarcastically": it sounds strange for me that alternative to Berkeley DB is HashMap. — Roman, Apr 04 '10 at 15:27
upvoting - question seems legit, and not that much sarcasm going around. Given, question could have stated from the start that hashmaps would not cut it. — tucuxi, Apr 04 '10 at 21:45
OK @Roman ... what **DO** you mean by "//sarcasam" in your comment below?? — Stephen C, Apr 05 '10 at 00:30
Why not check nosql-database.org --> Key Value / Store section and have an answer for yourself. Using IMDG , also a [Key Value Store](http://blogs.alachisoft.com/tayzgrid/using-an-in-memory-key-value-store-to-scale-java-apps/) ,gives you the option to scale — Basit Anwer, Dec 16 '15 at 06:47

score 8 · Answer 1 · edited Apr 14 '13 at 08:47

8

You can try Hazelcast. Just add hazelcast.jar to your classpath. And start coding

java.util.Map map = Hazelcast.getMap("myMap");

You'll get an in-memory, distributed, dynamically scalable data grid which performs super fast.

edited Apr 14 '13 at 08:47

om-nom-nom

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answered Aug 13 '10 at 11:08

Fuad Malikov

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cletus · Answer 2 · 2010-04-04T14:31:39.167

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Your question could mean one of two things.

If you mean a data structure for storing key-value pairs, use one of the Map instances that are a standard part of the JDK.

If however you are after an in-memory key-value store then I would suggest taking a look at EHCache or even memcached.

edited Apr 04 '10 at 14:31

answered Apr 04 '10 at 14:23

cletus

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@cletus : doesn't hashmap use in-memory key-value store? – Ashwin Jun 06 '12 at 04:25

score 3 · Answer 3 · answered Dec 06 '14 at 08:38

Chronicle-Map is a strong alternative.

Pure Java, simply java.util.Map implementation
Stores the data off-heap, optionally persisted to disk via memory-mapped files
Open source, permissive Apache 2.0 license
Incredibly fast, can manage millions of updates/queries per second (see exact numbers)

score 2 · Answer 4 · answered May 02 '12 at 04:17

I know this is a two-year old post but I've been messing around with Infinispan recently and I like it so far. I'm not an expert by any means but it was not too difficult for me to set up a distributed cache with a few nodes and I was pulling some data from them in about an hour.

score 2 · Answer 5 · answered Aug 11 '13 at 10:54

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MapDb is an alternative to Berkley with a friendly Apache 2 license.

Provides key-value store via java's Map interface
Lightweight (300KB jar)
Fast and threadsafe
Persists changes to disk if you want to
Many other features

answered Aug 11 '13 at 10:54

Andrejs

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Lightweight? mvn copy-dependencies collects some 14 MB for mapdb:3.0.5 – weberjn Jan 29 '18 at 13:27

score 2 · Answer 6 · answered Apr 04 '10 at 14:24

2

HashMap?

answered Apr 04 '10 at 14:24

Chris Dennett

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It lacks transactions management and possibility to keep some data in the disk and another part in-memory and so on.. //sarcasm – Roman Apr 04 '10 at 15:01
Ah, I see :) There was a problem a while back with someone wanting to develop stuff for Android but needed to use a storage-backed hashmap because the size of his data was too large. Something similar, I guess. – Chris Dennett Apr 04 '10 at 15:40

score 1 · Answer 7 · answered Apr 05 '10 at 05:13

jdbm works great for this sort of thing. It's intended for storing on disk in a paged file, provides for basic transaction support (no guarantees on isolation, but ACD are covered). We've used it in a production system with fairly wide deployment and have been quite pleased with the performance, stability, etc...

score 1 · Answer 8 · answered Apr 06 '10 at 23:21

1

Consider using jredis. It's a Java client for Redis, a persistent key-value store. There's also a JDBC driver for it: code.google.com/p/jdbc-redis/.

answered Apr 06 '10 at 23:21

Nathan Hurst

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Nikita Koksharov · Answer 9 · 2017-03-19T18:55:35.023

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I would recommend to try a Redisson. You will able to use distributed and scalable Map or ConcurrentMap and other (Set, List, Queue, Lock ...) implementations on top of high performance key-value Redis server.

Easy example:

Redisson redisson = Redisson.create();

ConcurrentMap<String, SomeObject> map = redisson.getMap("anyMap");

...

redisson.shutdown();

edited Mar 19 '17 at 18:55

answered Jan 12 '14 at 10:44

Nikita Koksharov

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score 0 · Answer 10 · answered Apr 04 '10 at 15:07

There are lightweigh or embedded dbs like HSQLDB, Derby, SQLite But like others don't understand why you need a db to store key/values...

Why not a Map? Need to keep key/values on app reboot?

Also it's perhaps not what you need but with html5 on up to date browsers you have localStorage that permits you to store key/values in the browser using javascript.

Looking for a lightweight java-compatible in-memory key-value store

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