code: public String[] getDevicesOfClass(final String tangoClass) throws DevFailed {
          if (!tangoClasses.containsKey(tangoClass)) {
              throw DevFailedUtils.newDevFailed(ExceptionMessages.CLASS_NOT_FOUND, tangoClass
                      + " does not exists on this server");
          }
          String[] deviceNames = new String[] {};
          for (final DeviceClassBuilder classBuilder : deviceClassList) {
              if (tangoClass.equalsIgnoreCase(classBuilder.getClassName())) {
                  final List<String> list = classBuilder.getDeviceNameList();
                  deviceNames = list.toArray(new String[0]);
                  break;
              }
          }
          return deviceNames;
      }
docs: Get the started devices of this server. WARNING: result is filled after
  server has been started
  
  @param tangoClass
  @return The devices
  @throws DevFailed