String userName = "TestAppMasterUser";
JobConf conf = new JobConf();
conf.set(MRJobConfig.MR_AM_STAGING_DIR, stagingDir);
ApplicationAttemptId applicationAttemptId = ConverterUtils
.toApplicationAttemptId(applicationAttemptIdStr);
JobId jobId = TypeConverter.toYarn(
TypeConverter.fromYarn(applicationAttemptId.getApplicationId()));
Path start = MRApps.getStartJobCommitFile(conf, userName, jobId);
Path end = MRApps.getEndJobCommitSuccessFile(conf, userName, jobId);
FileSystem fs = FileSystem.get(conf);
fs.create(start).close();