Soot - A Java optimization framework

Free and Open, Distributed, RESTful Search Engine

A decentralized bitcoin exchange network

CrateDB is a distributed and scalable SQL database for storing and analyzing massive amounts of data in near real-time, even with complex queries. It is PostgreSQL-compatible, and based on Lucene.

SpotBugs is FindBugs' successor. A tool for static analysis to look for bugs in Java code.

a fast, scalable, multi-language and extensible build system

Testcontainers is a Java library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.