title: How do I get the File Extention for a Mime Type (Content Type)
body: <p>There are tons of ways to get the Mime Type from a given InputStream or File.
  But given a MimeType or (in HTTP terms: content type) how do I get a list of file extensions.</p>
  
  <p>Java's activation library has 
  MimetypesFileTypeMap but that goes File Ext -> Mime Type. I need Mime Type -> File Ext.</p>
  
  <p>It seems like I would have to copy the pseudo private code that is in com.sun.activation to load up the mime type mappings. </p>