quartz定时任务插件问题，项目启动时job状态normal，一旦执行变为error?报错

创建任务代码片段，每次启动项目会正常生成job，状态为NORMAL

private void initXXXJob() throws SchedulerException {
		JobDetail jobDetail = JobBuilder
				.newJob(XXXJob.class)
				.withIdentity("XXXJob","XXXJob").build();

		CronTrigger trigger = TriggerBuilder
				.newTrigger()
				.withIdentity("XXXJob","XXXJob")
				.forJob(jobDetail).withSchedule(
						CronScheduleBuilder.cronSchedule("0 10 4 * * ? *"))
				.build();
		scheduler.scheduleJob(jobDetail, trigger);
	}

job类代码

@Component
public class XXXJob implements Job{
	
	@Logger
	static Log log;
	
	@Resource
	public XXXHome xxxHome;
	
	private static boolean isRunning = false;
	
	@Override
	public void execute(JobExecutionContext arg0) throws JobExecutionException {
		
		if(isRunning){ 
			return;
		}
		isRunning = true;
		try {
			xxxHome.download();
		} catch (Exception e) {
			e.printStackTrace();
			log.error(e.getMessage());
			isRunning = false;
		} finally{
			isRunning = false;
		}
		
	}
}

看不到任何报错啊，在execute方法里打断点，发现没有进入方法，每当执行之后，job的status就会变成ERROR，应该从什么地方考虑这个问题呢？