Use the Deploy-WAR Context Root dialog to provide missing context roots for WAR files:
Enter the context root (see below) for each WAR file listed in the Context Root column.
The context root is the base directory of the WAR file. The context root is used in the application as an alias for the WAR file. The Servlet Context uses the context root to resolve the path to the WAR file. Thus, the URL to the JSP or servlet takes this form:
hostname:port/contextRoot/<relative URLs in the WAR file>