Commonly used options include:
   -i <input> the source document as a file or URL.
   -n <name> the name of the created Java class.
   -a <uri> the namespace URI of the source document.
   -o <file> the file to write the generated class into.
   -o <dir> the directory in which the generated Java class is created.
            By default, output goes to stdout.
   -e <encoding> the encoding of the input document (N3, RDF/XML, etc).
   -c <config> a filename or URL for an RDF document containing
               configuration parameters.

Many other options are available. See the schemagen HOWTO in the
Jena documentation for full details.
请告知，这个原因是什么呀