IBM Lightweight Services (LWS) is a J2EE (JavaTM 2 Platform, Enterprise Edition) application that provides an event-driven hosting environment for lightweight services. Lightweight services are persistent, transactional, server-side programs developed in lightweight programming languages such as JavaScript and Python. Developers of these services have high-level, extensible access to IBM middleware, enabling services that communicate via Web services, Sametime instant messaging, and high-performance publish/subscribe.