code: public String[] getDeviceList(final String serverName, final String className) {
          String[] result = new String[0];
          final Server server = servers.get(serverName);
          if (server != null) {
              final String[] devices = server.getDevices(className);
              if (devices != null) {
                  result = Arrays.copyOf(devices, devices.length);
              }
          }
          return result;
      }
docs: Get devices of a server
  
  @return