ApplicationRunnerOperation getOperation(OptionSet options) {
      String rawOp = options.valueOf(operationOpt);
      return ApplicationRunnerOperation.fromString(rawOp);
    }
This class contains the main() method used by run-app.sh.
It creates the {@link ApplicationRunner} based on the config, and then run the application.
samza-core/src/main/java/org/apache/samza/runtime/ApplicationRunnerMain.java