private static boolean isCustomTestClass(String cmd) {
    Class<? extends Test> cmdClass;
    try {
      cmdClass =
        (Class<? extends Test>) PerformanceEvaluation.class.getClassLoader().loadClass(cmd);
      addCommandDescriptor(cmdClass, cmd, "custom command");
      return true;
    } catch (Throwable th) {
      LOG.info("No class found for command: " + cmd, th);
      return false;
    }
  }
Validates opts after all the opts are parsed, so that caller need not to maintain order of opts
hbase-diagnostics/src/main/java/org/apache/hadoop/hbase/PerformanceEvaluation.java