A fast SQL database that can run embedded or a server mode with support for transactions, encryption, full search, etc. Storage can be disk-based or in-memory.

HikariCP is a 'zero-overhead' production ready JDBC connection pool.

The MyBatis SQL mapper framework makes it easier to use a relational database with object-oriented applications. MyBatis couples objects with stored procedures or SQL statements using a XML descriptor or annotations.

Dropwizard Test Helpers

Jackrabbit content repository implementation

The Jdbi core API. Jdbi 3 is designed to provide convenient tabular data access in Java(tm) and other JVM based languages.

SqlObject is a declarative, annotation-driven API for database access. It complements the core API.

Pac4j: Security Configuration By Properties

The core classes of Apache Jackrabbit FileVault

Infinispan JDBC CacheStore module

Infinispan Query module