PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
QueryDSL - Unified Queries for Java. Contribute to querydsl/querydsl development by creating an account on GitHub.
Amazon Aurora - MySQL and PostgreSQL-compatible relational database built for the cloud. Performance and availability of commercial-grade databases at 1/10th the cost.
ClickHouse - ClickHouse is an open-source column-oriented database management system that allows generating analytical data reports in real time.
MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.
Hibernate - Hibernate an open source Java persistence framework project.