Source code of the SimplestHelloWorld portlet that is discussed here can be found at github.
	Like other Java EE applications, GateIn 3.5 portlets are packaged in the .war files. 
	A typical portlet .war file can include servlets, resource bundles, images, HTML, 
	JavaServer Pages (JSP), and other static or dynamic files.
The following is the directory structure of the SimplestHelloWorld portlet:
|-- SimplestHelloWorld-0.0.1.war | `-- WEB-INF | |-- classes | | `-- org | | `-- gatein | | `-- portal | | `-- examples | | `-- portlets| | `-- SimplestHelloWorldPortlet.class
| |-- portlet.xml
| `-- web.xml
| 
 | The compiled Java class implementing javax.portlet.Portlet (through javax.portlet.GenericPortlet ). | 
| 
 | This is the mandatory descriptor file for portlets. It is used during deployment. | 
| 
 | This is the mandatory descriptor for web applications. |