Recommend a database (pure Java, Schema less, embedded, in memory)

Question

Java

Please advise: pure Java, Schema less, embedded, in memory database.
To be used as a cache with the ability to search by object properties.

Well, or other options how to organize such a cache :)

Thank you!

Answer 1

Hypersonic in memory
H2 in memory

Answer 2

I may be wrong, but it seems to me that you can do without the database. Store everything in some data structure of your choice, like a HashMap, and serialize it to disk from time to time. Let's say in a separate thread every 0.1 sec. But of course, everything depends on the volume and consistency of the documents that you are going to store.

Answer 3

As for caching, a great thing is Ehcache. But this is purely a cache, i.e. banal Map, ala memcached (though with bells and whistles and can be embedded). It all depends on what attribute search capabilities you need - if everything is transparent and clear, then you can build simple indexes yourself and use it, it will be fast.
You can also take a look at Neo4J - this is an embedded graph-oriented database, a very good thing if your application falls on graphs.

Answer 4

And I recommend OrientDB. A very cool thing: all the more so since you can orient in the right direction: either by keyval, or Graph oriented, relational, etc.
www.orientdb.org/orient-db.htm

Answer 5

Take a look (sort of like a JSR-107 implementation with goodies) - commons.apache.org/jcs/index.html . There are many delicious things.