Agent mobility addresses some limitations faced by classic client/server architecture, namely, in minimizing bandwidth consumption, in supporting adaptive network load balancing and in solving problems caused by intermittent or unreliable network connections. There has been a great deal of attention on the potential productivity gains expected from so-called intelligent agents. These however require complex artificial intelligence (AI) functionality. Agents can realistically be of benefit in those areas concerned with autonomy and mobility. This is especially true of network management applications and this will be the focus of this paper.The paper discusses the usage of mobile agents and the advantages that these have over traditional client/server applications. It discusses the main characteristics of an agent, and shows how Java has the main components that allow mobile agents to be easily development. To show how agents are implemented it gives a practical implemented of an agent. Finally, the paper also discusses the main Java agent development systems, which are IBM aglets, Object Space Voyager and JATLite and outlines the advantages of using each of them.