JDK main-line development https://openjdk.org/projects/jdk

Hazelcast is a unified real-time data platform combining stream processing with a fast data store, allowing customers to act instantly on data-in-motion for real-time insights.

Jitsi is an audio/video and chat communicator that supports protocols such as SIP, XMPP/Jabber, IRC and many other useful features.

Distributed Stream and Batch Processing

Kronotop is a distributed document database that combines ACID transactions with simplicity at any scale.

Feature-complete implementation of the Raft consensus algorithm in Java