A cross-platform G-Code sender for GRBL, Smoothieware, etc.
VisualVM is an All-in-One Java Troubleshooting Tool
Distributed tracing system to gather timing data
iText for Java represents the next level of SDKs for developers
SoapUI is a free and open source cross-platform functional testing
Build great things at any scale
Gephi the open graph Viz platform
Pretty nice Zookeeper GUI, Support Win / Mac / Linux Platform
Visualizes all aspects of compiled Java class files
Get random, realtime read/write access to your Big Data
A high performance real-time analytics database
An XMPP server licensed under the Open Source Apache License
H2 is an embeddable RDBMS written in Java
ACHE is a web crawler for domain-specific search
Wrapper of syncthing for Android
Open source routing engine for OpenStreetMap
A free, open source, powerful tool for working with messy data
Distributed scheduled job framework
Efficient UDP unicast, UDP multicast, and IPC message transport
Apache Log4j 2 is a versatile, feature-rich, efficient logging API
Fast and usable source code search and cross reference engine
Dynamic Naming and Configuration Service
A graph database that supports more than 100+ billion data
eCommerce framework for multinational omnichannel installations
Additional plug-ins and extensions for Java's ImageIO