BLOB oracle com todos os tipos de arquivos e tenho que salvar o tipo correto de arquivo

String filename = "c:\\Java\\MyFile"; 
                      String sql = "  select stream, id from media where id = 77 ";
                      pst = con.prepareStatement(sql);
                      rs = pst.executeQuery();
                      FileOutputStream os2=new FileOutputStream(new File(filename));
                      byte[] buf = new byte[100 * 11024];
                       while (rs.next()){
                           BufferedInputStream documentData = new  BufferedInputStream(rs.getBinaryStream(1));
                           int len;
                           while ((len = documentData.read(buf, 0, buf.length)) != -1)
                           {
                               os2.write(buf, 0, len);
                           }
                       }