Quartz trigger doesn't fire when using JobStoreTX - quartz-scheduler

Question

I am configuring Quartz for my application under IBM Liberty Profile. When I used the default RAMJobStore. The trigger was fired and the scheduled job ran. Here are the codes:
JobDetail job = JobBuilder.newJob(QuartzBatchJobs.class).build();
Trigger trigger = TriggerBuilder.newTrigger().startNow().build();
try {
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
scheduler.start();
scheduler.scheduleJob(job, trigger);
} catch (Exception e) {
System.out.println(e.toString());
}
However, when I switched to jdbcjobstore JobStoreTX and ran the application, all the quartz tables were updated but the trigger itself wasn't fired and the job didn't run. Here is my quartz.properties:
org.quartz.threadPool.threadCount = 10
org.quartz.jobStore.class = org.quartz.impl.jdbcjobstore.JobStoreTX
org.quartz.jobStore.driverDelegateClass=org.quartz.impl.jdbcjobstore.StdJDBCDelegate
org.quartz.jobStore.tablePrefix=QRTZ_
org.quartz.jobStore.dataSource=quartzRepo
org.quartz.dataSource.quartzRepo.jndiURL=jdbc/quartzRepo
Here is the server.xml of Liberty Profile for data source.
<dataSource id="quartzRepo" jndiName="jdbc/quartzRepo" type="javax.sql.XADataSource" isolationLevel="TRANSACTION_READ_COMMITTED">
<jdbcDriver libraryRef="DB2Jcc4Lib" />
<properties.db2.jcc currentSchema="qrtz" databaseName="localdb2" password="${jdbc.quartzRepo.password}" portNumber="50000" serverName="localhost" user="${jdbc.quartzRepo.user}" driverType="4" />
</dataSource>
Could you guys please give me some suggestions on this issue? Thanks!