This book teaches you all about using Apache Geronimo, the open source lightweight J2EE/Java EE 5 web application server. Geronimo's GBeans enable you to deploy sophisticated server-side enterprise Java applications and perform special enterprise-level Java development for transactional support. Geronimo is unique in that it's the only open source lightweight deployment tool around. It also has the capabilities for Spring compliance, so you Spring developers can deploy your web applications using Geronimo. Meanwhile, JBoss is the only other significant open source J2EE container out there. Geronimo, now backed by IBM, is incorporated into IBM's WebSphere Community Edition/Package.