Java and Distributed Systems: Observations, Experiences, and ... a Wish List

When Java was introduced to the world at large 20 years ago, it brought many interesting features and capabilities into the mainstream computing environment. A Virtual Machine based approach with a just-in-time compiler that supported sandboxing, dynamic class loading, and introspection enabled a number of novel and innovative network-based applications to be developed. While many of these capabilities existed in some fashion in other prototype and experimental languages, the combination of all of them in a popular general purpose language opened up the possibility of building real systems that could leverage these capabilities. Applets, Jini, JXTA, and many other innovative concepts were introduced over the course of time, building on top of the basic capabilities of Java. This talk will present some personal experiences with using Java in distributed computing environments ranging from mobile software agents to distributed resource sharing to process integrated mechanisms. The basis for many of these capabilities is the Aroma Virtual Machine, a custom Java compatible VM with state capture, migration, and resource control capabilities. Motivations behind the Aroma VM will be discussed, along with design choices and some results. Finally, the talk will discuss a wish list of features that would be nice to have in future versions of Java to enable many more novel applications to be developed.