GlassFish is an open source application server project led by Sun Microsystems for the Java EE platform. The commercial version is called Sun GlassFish Enterprise Server. GlassFish is free software, dual-licensed under two free software licences: the Common Development and Distribution License (CDDL) and the GNU General Public License (GPL) with the classpath exception.
GlassFish is based on source code donated by Sun and Oracle Corporation's TopLink persistence system. It uses a derivative of Apache Tomcat as the servlet container for serving Web content, with an added component called Grizzly which uses Java NIO for scalability and speed.

http://en.wikipedia.org/wiki/GlassFish
https://glassfish.dev.java.net/