How to rename job class for persistent Quartz Jobs? - spring

Question

I have a test quartz job like this one.
package com.example.spring.quartz.basic;
import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
public class ExampleJob implements Job
{
#Override
public void execute(JobExecutionContext context) throws JobExecutionException
{
JobDataMap map = context.getMergedJobDataMap();
String timeout = (String)map.get("timeout");
System.out.println("ExampleJob.execute() " + timeout);
}
}
This job is persistent so it is written to the database, and it seems that Quartz writes the full qualified job class name com.example.spring.quartz.basic.ExampleJob to the database.
So if refactor rename the ExampleJob to ExampleJob2 I end up with the exception below because quartz looks for ExampleJob and gets a class not found exception.
Question: Is there some trick, or pattern I can use to be able to safely rename my job classes
without causing existing job definitions to break?
Exception in thread "main" org.springframework.context.ApplicationContextException: Failed to start bean 'quartzScheduler'; nested exception is org.springframework.scheduling.SchedulingException: Could not start Quartz Scheduler; nested exception is org.quartz.SchedulerConfigException: Failure occured during job recovery. [See nested exception: org.quartz.JobPersistenceException: Couldn't retrieve trigger: com.example.spring.quartz.basic.ExampleJob [See nested exception: java.lang.ClassNotFoundException: com.example.spring.quartz.basic.ExampleJob]]
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:170)
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:51)
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:339)
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:143)
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:108)
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:945)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at com.example.spring.quartz.transactional.QuartzExampleJobMain.main(QuartzExampleJobMain.java:16)
Caused by: org.springframework.scheduling.SchedulingException: Could not start Quartz Scheduler; nested exception is org.quartz.SchedulerConfigException: Failure occured during job recovery. [See nested exception: org.quartz.JobPersistenceException: Couldn't retrieve trigger: com.example.spring.quartz.basic.ExampleJob [See nested exception: java.lang.ClassNotFoundException: com.example.spring.quartz.basic.ExampleJob]]
at org.springframework.scheduling.quartz.SchedulerFactoryBean.start(SchedulerFactoryBean.java:715)
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:167)
... 9 more
Caused by: org.quartz.SchedulerConfigException: Failure occured during job recovery. [See nested exception: org.quartz.JobPersistenceException: Couldn't retrieve trigger: com.example.spring.quartz.basic.ExampleJob [See nested exception: java.lang.ClassNotFoundException: com.example.spring.quartz.basic.ExampleJob]]
at org.quartz.impl.jdbcjobstore.JobStoreSupport.schedulerStarted(JobStoreSupport.java:683)
at org.quartz.core.QuartzScheduler.start(QuartzScheduler.java:526)
at org.quartz.impl.StdScheduler.start(StdScheduler.java:143)
at org.springframework.scheduling.quartz.SchedulerFactoryBean.startScheduler(SchedulerFactoryBean.java:649)
at org.springframework.scheduling.quartz.SchedulerFactoryBean.start(SchedulerFactoryBean.java:712)
... 10 more
Caused by: org.quartz.JobPersistenceException: Couldn't retrieve trigger: com.example.spring.quartz.basic.ExampleJob [See nested exception: java.lang.ClassNotFoundException: com.example.spring.quartz.basic.ExampleJob]
at org.quartz.impl.jdbcjobstore.JobStoreSupport.retrieveTrigger(JobStoreSupport.java:1524)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.recoverMisfiredJobs(JobStoreSupport.java:968)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.recoverJobs(JobStoreSupport.java:855)
at org.quartz.impl.jdbcjobstore.JobStoreSupport$1.execute(JobStoreSupport.java:827)
at org.quartz.impl.jdbcjobstore.JobStoreSupport$46.execute(JobStoreSupport.java:3764)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.executeInNonManagedTXLock(JobStoreSupport.java:3798)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.executeInNonManagedTXLock(JobStoreSupport.java:3760)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.recoverJobs(JobStoreSupport.java:823)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.schedulerStarted(JobStoreSupport.java:681)
... 14 more
Caused by: java.lang.ClassNotFoundException: com.example.spring.quartz.basic.ExampleJob
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:623)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1610)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1515)
at java.io.ObjectInputStream.readClass(ObjectInputStream.java:1481)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1331)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1989)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1913)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1796)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
at java.util.HashMap.readObject(HashMap.java:1155)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1891)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1796)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1989)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1913)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1796)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
at org.quartz.impl.jdbcjobstore.PostgreSQLDelegate.getObjectFromBlob(PostgreSQLDelegate.java:103)
at org.quartz.impl.jdbcjobstore.StdJDBCDelegate.selectTrigger(StdJDBCDelegate.java:1764)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.retrieveTrigger(JobStoreSupport.java:1520)
... 22 more

Answer 1

A nice problem to encounter with.
Is there some trick
Yes, the trick is to redefine your job with new details.
Check this for howto.
Hope this solves your problem.

Answer 2

To elaborate on Sinchan's answer:
If you have enough data to recreate the jobs (i.e. with expiration date already on file, email a reminder to employees 30 days before their license expires), write a utility to unschedule/delete all existing jobs of that type and recreate them with the new type.
Otherwise:
After renaming the class, create an empty ExampleJob class which extends ExampleJob2. This should allow Quartz to read in the existing tasks.
Create a utility program that reads in each ExampleJob, immediately schedules a corresponding ExampleJob2 with the same properties, and deletes the ExampleJob.
At this point, you should be able to remove the ExampleJob class.