Tomcat is the servlet container that is used in the official Reference Implementation for the Java Servlet and JavaServer Pages technologies. The Java Servlet and JavaServer Pages specifications are developed by Sun under the Java Community Process. Tomcat is developed in an open and participatory environment and released under the Apache Software License. Tomcat is intended to be a collaboration of the best-of-breed developers from around the world.

Jetty is a 100% Java HTTP Server and Servlet Container. This means that you do not need to configure and run a separate web server (like Apache) in order to use java, servlets and JSPs to generate dynamic content. Jetty is a fully featured web server for static and dynamic content. Unlike separate server/container solutions, this means that your web server and web application run in the same process, without interconnection overheads and complications. Furthermore, as a pure java component, Jetty can be simply included in your application for demonstration, distribution or deployment. Jetty is available on all Java supported platforms.Open Source Jetty is devloped under the guidance of Mort Bay Consulting and released under the Apache 2.0 License. The Jetty user and development community is active and welcomes new contributors.

The Resin® high-performance application server features load balancing for increased reliability. Resin encourages separation of content from style with its fast XML and XSL support. Resin's ease of use saves engineering time and staff costs.

JOnAS (Java Open Application Server) is a pure Java open source implementation of the EJB (Enterprise JavaBeans) specification. JOnAS is the Open Source implementation by ObjectWeb of the J2EETM specification. JOnAS is a pure JavaTM implementation of this specification that relies on the JDK. JOnAS is part of the ObjectWeb Open Source initiative, which was launched in collaboration with several partners including Bull, the France Telecom R&D division and INRIA.

W3C's Server - Jigsaw is W3C's leading-edge Web server platform, providing a sample HTTP 1.1 implementation and a variety of other features on top of an advanced architecture implemented in Java. The W3C Jigsaw Activity statement explains the motivation and future plans in more detail. Jigsaw is an W3C Open Source Project, started May 1996. See the license for details.

Servlet Engine and Open Source library.

LiteWebServer™ (LWS) is a small (roughly 1 MB), modular web server and Java web container. It is based on code from Apache's popular Tomcat server, tweaked and extended for easier installation and management, with professional support services offered through various types of support licenses. LWS consists of a set of modules that can be installed separately, so you only need to install and manage exactly the features you need. The base module provides basic web server features (HTTP/1.1 support) and support for the Servlet API. Add-on modules provide additional features, such as JSP support. Click on a module name in the left menu to learn more about it.

Xerver is an advanced free GNU GPL Web and FTP server. Xerver brief feature list:

Very fast and low memory usage.

GNU GPL open source.

Contains all features the larger web servers offers:

PHP and Perl support

FTP server included

Virtual directories

Password protected folders

Customized error messages ("404 Not Found")

Link