Sun GlassFish Enterprise Server 2.1 is available as part of the Java EE 5 SDK.
There are two Java EE 5 SDK versions:
In addition, you can download these SDK distributions with the JDK or with the NetBeans 5.5.1 tools. For more information, access the download page at http://java.sun.com/javaee/downloads/index.jsp.
GlassFish v2.1 and Enterprise Server 2.1 does not work with NetBeans 5.5 for developing Java EE applications. You must use NetBeans 5.5.1.