The Portal Server software includes an API which is an extension to JSR-168 Portlets, in the com.sun.portal.portlet Java package. Using this API, JSR-168 portlets will be able communicate with each other even if they are in different web applications. It is assumed that all these portlets will be on the same instance of a Portal Server and running inside the Portal Server Portlet container. This API uses event generation and notification to convey the information/data among portlets. The event notification will be for the portlets which have registered themselves for listening to that particular event.