private static Class<? extends TestBase> determineCommandClass(String cmd) {
    CmdDescriptor descriptor = COMMANDS.get(cmd);
    return descriptor != null ? descriptor.getCmdClass() : null;
  }
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