code: public Schema compileSchema( InputStream stream, String systemId )
  		throws VerifierConfigurationException, SAXException, IOException {
  		
  		InputSource is = new InputSource(stream);
  		is.setSystemId(systemId);
  		return compileSchema(is);
  	}
docs: processes a schema into a Schema object, which is a compiled representation
  of a schema.
  
  The obtained schema object can then be used concurrently across multiple
  threads.
  
  @param	systemId
  The system Id of this input stream.