Usually the default way the server figures out the MIME type is by calling the type-by-extension function. This function instructs the server to look up the MIME type according to the requested resource’s file extension in the MIME types table. This table was created during virtual server initialization by the MIME types file (which is usually called mime.types).
For example, the entry in the MIME types table for the extensions .html and.htm is usually:
which says that all files with the extension .htm or .html are text files formatted as HTML, and the type is text/html.
Note that if you make changes to the MIME types file, you must reconfigure the server before those changes can take effect.
For more information about MIME types, see Sun Java System Web Server 6.1 SP12 Administrator’s Configuration File Reference.