Computer-supported cooperative work (CSCW) supports groups with communication and coordination during the execution of their activities. It allows physically dispersed teams to engage in a common task by providing an interface to a shared workspace. A variety of synchronous applications are playing a major role in distance education, joint program development, cooperative publishing, etc. These applications are usually platform-dependent, groupware programmers have to develop new applications for each groupware platform. In this paper, we present a developing environment called CollabRunJava. Users can collaborate to design and process their job and can also develop groupware only concentrate on application-specific details on our system. CollabRunJava supports 2 modes for developing applications. In the instant-develop mode, user can immediately execute and test the classes. In the runtime-evolution mode, user can observe application behavior, debug applications and change the running applications codes without re-execution. Our system can be further enhanced by using plug-in components with the above mechanisms. For example, with the aid of visualization components, our system can help users explore program behavior. In addition, all these activities can be performed in a collaborative way. This makes it also helpful for distant learning and program testing.