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.

Spring JDBC provides an abstraction layer that simplifies code to use JDBC and the parsing of database-vendor specific error codes.

The Apache Commons CSV library provides a simple interface for reading and writing CSV files of various types.

jOOλ is part of the jOOQ series (along with jOOQ, jOOX, jOOR, jOOU) providing some useful extensions to Java 8 lambdas.

JIRA provides cutting edge issue tracking and project management.

Nutz, which is a collections of lightweight frameworks, each of them can be used independently

Oak Core

Hibernate based persistence module

Oak JCR Binding

The Beangle Data Library

core for Seata built with Maven