The MIME types file in the config directory contains mappings between MIME (Multipurpose Internet Mail Extensions) types and file extensions. For example, the MIME types file maps the extensions .html and .htm to the type text/html:
When the Sun Java System Web Server receives a request for a resource from a client, it uses the MIME type mappings to determine what kind of resource is being requested.
MIME types are defined by three attributes: language (lang), encoding (enc), and content-type (type). At least one of these attributes must be present for each type. The most commonly used attribute is type. The server frequently considers the type when deciding how to generate the response to the client. The enc and lang attributes are rarely used.