Joeq: A virtual machine and compiler infrastructure. Joeq1 is a virtual machine and compiler infrastructure designed to facilitate research in virtual machine technologies such as Just-In-Time and Ahead-Of-Time compilation, advanced garbage collection techniques, distributed computation, sophisticated scheduling algorithms, and advanced run time techniques. Joeq is entirely implemented in Java, leading to reliability, portability, maintainability, and efficiency. It is also language independent, so code from any supported language can be seamlessly compiled, linked, and executed -- all dynamically. Each component of the virtual machine is written to be independent with a general but well-defined interface, making it easy to experiment with new ideas. Joeq is released as open source software, and is being used as a framework by researchers all over the world on topics ranging from automatic distributed virtual machines to whole-program pointer analysis.