There are some screenshots from their demo site.
“The main asset of the Caltech Laboratory for Experimental Finance (CLEF) is its markets software, called jMarkets. It allows us to run large-scale financial markets experiments reliably and flexibly over the web. jMarkets is pure-Java and J2EE compliant. It was developed from the beginning to become open-source, and a first release to the academic community is planned for 15 November 2004. We decided to make jMarkets open source, in order to promote experimental research on financial markets. Our research to date has demonstrated the potential of experiments, paving the way to investigating longstanding questions. But many more exciting questions exist than we can address on our own. jMarkets’ features will make it accessible to other research groups, usable in a variety of locations and populations. It is to become a tool to which many research groups will have easy access and to which they will be able to contribute.”
jMarkets is meant to provide the infrastructure for running large-scale experiments. It is built around a specific theoretical framework, namely, General Equilibrium Theory (GE). This is the branch of Economics that studies large, competitive, interdependent systems.
…
Peter Bossaerts and William Zame are the scientific supervisors of the jMarkets project; Walter Yuan is the technical supervisor; Raj Advani is the lead programmer.