code: public void setDoctype(String doctypeSystem, String doctypePublic)
      {
          setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, doctypeSystem);
          setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, doctypePublic);
      }
docs: Set the value coming from the xsl:output doctype-public and doctype-system stylesheet properties
  @param doctypeSystem the system identifier to be used in the DOCTYPE
  declaration in the output document.
  @param doctypePublic the public identifier to be used in the DOCTYPE
  declaration in the output document.