In the File References property page, you can provide a list of , map JSP Tag Library references to in the WAR file, and map errors to URLs for resources to be called to process the error.
To add welcome files to the list:
To delete a file from the list, select the row containing the file and click Delete. A confirmation dialog will ask you if you really want to delete the file from the list.
In the JSP Tag Libraries section, list the tag library references in the code of components in the WAR and the locations of the corresponding (TLDs).
To delete a tag library from the list, select the tag library and click Delete. A confirmation dialog will ask you if you really want to delete the tag library from the list.
In the Error mapping section of the File References dialog box, you can indicate the URL that must be accessed when a particular error occurs. For example, you could enter `404' in the Error/exception column and `404.html' in the URL column to indicate that the 404.html file should be opened when the 404 error occurs.
To delete a mapping from the list, select the row containing the mapping and click Delete.
A confirmation dialog will ask you if you really want to delete the mapping from the list.