Zipkin is a distributed tracing system

Very spicy additions to the Java programming language.

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory. It is a fast and easy to use embedded Java database engine.

Fast scalable time series database

A stand-alone Bloom filter implementation written in Java

a UI for OpenTSDB

BSD-licensed display and interaction library for tile-based maps in Processing

Merb/Rails style routes for Java