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MapDB: database engine

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MapDB combines embedded database engine and Java collections. It is free under Apache 2 license. MapDB is flexible and can be used in many roles:

Hello world

Maven snippet, VERSION is Maven Central

<dependency>
    <groupId>org.mapdb</groupId>
    <artifactId>mapdb</artifactId>
    <version>VERSION</version>
</dependency>

Hello world:

//import org.mapdb.*
DB db = DBMaker.memoryDB().make();
ConcurrentMap map = db.hashMap("map").make();
map.put("something", "here");

You can continue with quick start or refer to the documentation.

Support

More details.

Development

MapDB is written in Kotlin, you will need IntelliJ Idea.

You can use Gradle to build MapDB.

MapDB is extensively unit-tested. By default, only tiny fraction of all tests are executed, so build finishes under 10 minutes. Full test suite has over million test cases and runs for several hours/days. To run full test suite, set -Dmdbtest=1 VM option.

Longer unit tests might require more memory. Use this to increase heap memory assigned to unit tests: -DtestArgLine="-Xmx3G"

By default unit tests are executed in 3 threads. Thread count is controlled by -DtestThreadCount=3 property

On machine with limited memory you can change fork mode so unit test consume less RAM, but run longer: -DtestReuseForks=false