GlassFish is the reference implementation of Java EE developed by Oracle. In fact, the project originated in 2005 with the opening of the Sun Application Server. The first version of GlassFish (1.0) was released in 2006.
In particular, GlassFish boasts a comprehensive admin interface and a complete shell allowing for command line administration of the server. In terms of standards, GlassFish is a complete implementation of Java EE 7, covering: EJB 3.2, JPA 2.1, JAX-RS 2.0, JSF 2.2, Servlet 3.1, CDI 1.1, etc.
GlassFish is distributed under either the CDDL or the GPL v2.
It is written in Java.