Hazelcast

Clustering and highly scalable data distribution platform for Java.
PopSQL

Modern SQL editor for teams.
Apache HBase

Apache HBase – Apache HBase™ Home.
MemSQL

Database for real-time transactions and analytics.
Apache Cassandra

The Apache Cassandra database is the right choice when you need scalability and high availability without compromising performance.
ArangoDB

A distributed open-source database with a flexible data model for documents, graphs, and key-values.
MySQL Community Edition

MySQL :: MySQL Community Edition.
H2 Database Engine

H2 is a relational database management system written in Java.
MyTaskHelper

MTH is a relational online database and web-form builder.
PostgreSQL

PostgreSQL is a powerful, open source object-relational database system.