Web services are software systems designed to support interoperable machine-to-machine interaction over a network. SOAP (Simple Object Access Protocol) is used for exchanging messages between computers and is necessary for web services to communicate, with XML being the format for SOAP messages. Axis is an implementation of SOAP that works over the Apache Tomcat HTTP server, which can be used to install and configure a web services environment to develop a simple Java web service and J2ME mobile client application.