code: public String[] get_server_class_list(Database database, String serverName) throws DevFailed {
          if (!database.isAccess_checked()) checkAccess(database);
  
          DeviceData argIn = new DeviceData();
          argIn.insert(serverName);
          DeviceData argOut = command_inout(database, "DbGetDeviceServerClassList", argIn);
          String[] list = argOut.extractStringArray();
          //	Extract DServer class
          int nb_classes;
          if (list.length==0)
              nb_classes = 0;
          else
              nb_classes = list.length - 1;
          String[] classes = new String[nb_classes];
          for (int i = 0, j = 0 ; i<list.length && j<nb_classes ; i++)
              if (!list[i].equals("DServer"))
                  classes[j++] = list[i];
          return classes;
      }
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