During the ObjectType step in the request handling process, the server determines the MIME type attributes of the resource requested by the client. Several different server application functions (SAFs) can be used to determine the MIME type, but the most commonly used one is type-by-extension. This function tells the server to look up the MIME type according to the requested resource’s file extension in the MIME types table.
The directive in obj.conf that tells the server to look up the MIME type according to the extension is:
If the server uses a different SAF, such as force-type, to determine the type, then the MIME types table is not used for that particular request.
For more details of the ObjectType step, see the Sun Java System Web Server 6.1 SP9 NSAPI Programmer’s Guide.