Distributed Java Support for Mobile Applications on Lightweight Devices

Mobile computers and personal digital assistants are now widely affordable and are powerful enough to run paradigm shifting mobile applications and support programming environments like Java. We are investigating the support services and software infrastructure that is needed for the next generation of mobile users and applications that will use such devices. As well as email, messaging and web based applications that are already prevalent on wireless laptops and PDAs we are investigating context-aware applications that play an active role on their users’ behalf and taking actions dependent upon spatial and temporal information. Systems such as Fox’s Garnet environment have shown that mobile chat and collaborative environments can be built using PDAs and Java and message-oriented middleware. Java is a particularly attractive development environment for smart mobile applications allowing for a considerably richer higher level set of development libraries and components than would be possible using traditional embedded systems languages. In this paper we consider two mobile user application categories. Firstly the mobile householder or office based worker or scientist who is mobile within the context of one or more building zones and who might wish to interact with devices and other users in his/her environment. Secondly we consider a field worker who might be a field scientist gathering data or a soldier in a battlefield scenario. This sort of user is working in a more hostile environment with more likelihood of poor network coverage or temporary disruption to services. He/she might wish to operate in “nomadic” mode between periods of connectivity. We wish to add mobile location context to a smart agent based software infrastructure to allow more pro-active mobile applications. We also consider the necessary mobile support environment from the perspective of a smart mobile device. We are working with swarm based mobile networked robots [7] which have similar computational power to a PDA but which carry sensors and are controlled by an agent based software system. Our goal is to investigate the issues surrounding a interoperating mobile software support structure that can be scaled to cope with large numbers of participating nodes both humans represented by their PDA proxies and robots represented by agent based control systems. In this paper we discuss the Java support environments we have experimented with; the performance of the base components and our observed trends for mobile Java; and our architecture for a mobile support environment using Java: network; thread; introspection and communications packages. We also discuss our use of WaveLAN and Bluetooth communications systems from Java and also the use of location context information to enrich potential mobile applications behaviour [6]..