"JRun is a server-side Java(TM) Web application deployment environment. JRun includes an integrated Web server as well as extensions that add the functionality of server-side Java (Java Servlets) to an existing Web server. The release of JRun 2.3 expands the feature set and capabilities to include support for the latest Servlet API 2.2.1 and support for the JavaServer Pages(TM) (JSP) 0.92 specification.
In addition, JRun 2.3 allows users to run Java servlets (platform-independent, server-side programs written using the Java Servlet API) in conjunction with all of the industry standard Web servers including Microsoft's IIS and PWS, Netscape's servers, Apache, O'Reilly's WebSite, and StarNine's WebStar."
JRun comes in two flavors, JRun and JRun Pro. JRun is available as a free download from the company's web site. JRun Pro 2.3 is priced at US$595.