Apache Geronimo!

JBoss is Red Hats Java EE 5-compliant (soon Java EE 6-compliant) application server. It is, as with Red Hat itself, dual-licensed either as open source (community edition) or commercially (enterprise edition).

appserver.io is a multithreaded application server for php written in php. Our technology allows real multi-threading in PHP and different useful services for developers enabling more efficiency and security. And best of all – it is completely open source!

GlassFish v3, built by the GlassFish community, is the first compatible implementation of the Java EE 6 platform specification. Many of the Java EE 6 themes carry over to Sun GlassFish Enterprise Server v3 - flexibility, extensibility, and developer ease of use. This lightweight, flexible, and open-source application server enables organizations to not only leverage the new capabilities introduced within the Java EE 6 specification, but also to add to their existing capabilities through a faster and more streamlined development and deployment cycle. »

Oracle WebLogic Server 12c is the #1 application server across conventional and cloud environments, providing extreme cloud performance, scalability, and elasticity.

WebSphere Application Server provides the availability and security your business depends on while optimizing cost.

JOnAS is a leading edge Java EE 5 certified Open Source OSGi Enterprise Server by OW2. The License used by JOnAS is the LGPL. The OW2 development community includes many academic institutes (Grenoble University, INRIA, LIFL, Peking University, UPM, ...) working with JOnAS; this fastens technology transfers and make JOnAS a top level product in term of technology innovation. JOnAS 5 is designed with an OSGiTM based services architecture to provide a dynamically adaptable application server. JOnAS implements the full Java EE 5 execution stack and provides, with EasyBeans, an efficient, pluggable and easy to use EJB3 container. »

The Mako Server is an application server with an API that loosely resembles the Java Servlet API, but where server side web applications are designed in the Lua scripting language. The Mako Server is capable of delivering dynamically generated content faster than Apache can deliver static content.