JBoss

JBoss Application Server (or JBoss AS) is a free software / open source Java EE-based application server. Because it is Java-based, JBoss AS is cross-platform, usable on any operating system that Java supports.
JBoss AS 4.0 is a J2EE 1.4 application server, with embedded Tomcat 5.5. Any JVM between 1.4 and 1.5 is supported. JBoss can run on numerous operating systems including many POSIX platforms like RHEL and MacOS X, Windows, and others, as long as a suitable JVM is present.
JBoss AS 4.2 is also a J2EE 1.4 application server, but EJB 3 is deployed by default. It requires JDK 5. Tomcat 6 is bundled with it. DocFamily supports Jboss Application Server in its current version for its server-based products.