The Geronimo project is a free software application server developed by the Apache Software Foundation and distributed under the Apache license.
Geronimo is currently compatible with the Java 2 Platform, Enterprise Edition (J2EE) 1.4 specification. When compared to other application servers such as JBoss, WebLogic and WebSphere, Geronimo's most distinctive features are its:
Software consulting giant IBM has provided considerable support to the project through marketing, code contributions, and the funding of several project committers. In October 2005, IBM announced a free edition of its WebSphere application server named Websphere Application Server Community Edition suite based on Geronimo.
Other commercial supporters include AMD, Chariot Solutions, Simula Labs and Virtuas.

Modular GBean-based architecture, which allows users to remove unneeded services and build very lightweight configurations of the server
Non-Profit ASF leadership, which provides legal protection, ensures stability across the loss of individual contributors and insulates the project from commercial conflicts of interest
Diverse support community, in which companies compete freely and openly to provide services, with none enjoying any particular trademark advantage History

Matrix of Application Servers