We can add this resource reference by opening our application's web.xml
deployment descriptor (located under the Configuration Files folder), clicking on
the References button in the tool bar, then expanding the Resource References node,
and clicking on the Add... button.
For our purposes, all we need to do is add a value for the Resource Name text field.
The value of this field must be the Java Naming and Directory Interface ( JNDI )
name of the data source we wish to use with our application. In our specific example,
this JNDI name is jdbc/sample .
After entering the resource name for our datasource and clicking OK , we can see it
listed in the Resource References section of our application's web.xml .