Jetty is  an open-source, standards-based, full-featured  web server implemented
entirely in Java. It  is released under the Apache 2.0  licence and is therefore
free for commercial use and distribution.

Jetty can be used as:

    * a stand-alone traditional web server for static and dynamic content
    * a dynamic content server behind a dedicated HTTP server such as Apache
      using mod_proxy
    * an embedded component within a Java application

Some of the defining features of Jetty are:

Simplicity:  The guiding principle of Jetty  could be said to be "simplicity not
complexity".  We want to make Jetty easy to understand and use:

Efficiency:   A lot  of  effort  goes into  optimizing  Jetty's performance  and
crafting the code so as to make the footprint as small as possible.

Embeddability:  Jetty is designed to be a good component. This means that it can
easily be embedded in an application without forcing the application to adapt to
it.

Pluggability:  Jetty  is architected for pluggability. The  API allows different
implementations  of all  of the  principal Jetty  components to  be selected. At
least  one,  but sometimes  more,  implementations  of  a component  are  always
provided. However if these do not meet your needs, you are free to code your own
using the  interfaces and  abstract classes  as a  basis. This means  that Jetty
can  be  easily customised  to  a  particular application  environment. This  is
particularly useful when Jetty is acting as  the web container in a J2EE server,
as Jetty's pluggability ensures a tight integration with a host container.

WWW: http://jetty.mortbay.com/