SoapUI is a free and open source cross-platform functional testing
Programmer-friendly testing framework for Java and the JVM
The OWASP ZAP core project
Test automation made simple
Most popular Mocking framework for unit tests written in Java
Coverage-guided, in-process fuzzing for the JVM
State of the art mutation testing system for the JVM
The Open Source Test Automation Platform
Android unit testing framework
Database Subsetter and Relational Data Browser
Editor for Fixed Width, Csv and Existing Xml files.
A web application for testing webservices
Simple example of draw and rotate 3D box
A C++ library for AVR and NodeMCU
Selenium HTML reporter for TestNG
A tool that inserts code into Java class files for logging
Software Unit Tests (Language Independent Approach)
CAT is the basic component of the server project
SikuliX version 2.0.0+ (2019+)
Java-based test automation framework (Maven + TestNG)
Test Automation Management Tool
Modbus slave simulator
Marathon supports testing of Java/Swing and Java/Fx applications.