OpenEJB is a simple, lightweight Enterprise JavaBeans (EJB) container and server. You can embed OpenEJB in your own applications, or in a Web application server like Tomcat, or run it as a standalone EJB server. It supports EJB 3.0, 2.1, 2.0, and 1.1, and has partial support for EJB 3.1.
Echomine Feridian is an easy-to-use Java API that gives you quick and easy access to the XMPP network used in IM services such as Google Talk. The API allows you to communicate with Jabber/XMPP servers for sending and receiving instant messages, presence management, and custom extensions to the XMPP protocol.
Luxor is an open-source XML User Interface Language (XUL) toolkit in Java that lets you build UIs using XML and also includes an ultra light-weight, multi-threaded Web server, a portal engine, and a template engine. It is also Web Start-ready, as everything fits in a jar and requires no loose files.
Studs MVC Framework+ contains a port of Apache's Jakarta Struts to PHP, though the libraries included in the rest of the project are much more vast. In order to implement the Struts port, it was necessary to build a core, object-oriented API in the style of the JDK and the Jakarta Commons, a servlet container to handle HTTP requests and to invoke servlet classes, and finally, a parsing engine for JSP-style template pages. In the end, the result is an environment which is very similar to that provided by a J2EE Web Container, only everything is implemented in PHP. While it was possible to carry over many of the concepts, designs and mechanisms from J2EE, some limitations do exist due to the nature of the PHP programming language, such as the lack of checked exceptions (runtime only).