Java

We chose Java as a programming language for our implementation for three key reasons:

• Applets for downloadable code. DCAs designed as applets bring the application to the client's machine. Caching policies and behavior can be imposed by changing the code that the clients download.
• Built in support for graphics, networking, and multithreading. Multiart's graphical user interface (GUI) uses the Java Abstract Windowing Toolkit (AWT) for handling user interaction. The Relay servers and caches use Java's networking application programmer's interface (API) for creating network connections. Finally, the Relay server uses Java's multithreading capabilities to service multiple clients simultaneously.
• Object serialization. Object serialization gives us a generic mechanism for sending objects between the Relay servers and caches. It works nicely with application-specific data because object serialization supports transmission of all objects, regardless of their complexity.

More details of how these features are used are given in the following sections on Relay and Multiart.