This overwrites bean defined in singlestep-partition-support.xml which is pulled by ftphdfs.xml.

```xml
<bean id="jobExplorer" class="org.springframework.batch.core.explore.support.SimpleJobExplorer">
  <constructor-arg ref="jobInstanceDao" />
  <constructor-arg ref="jobExecutionDao" />
  <constructor-arg ref="stepExecutionDao" />
  <constructor-arg ref="executionContextDao" />
</bean>
```

Dave said that these DAOs are not created as beans not in batch or boot. So I'm still having a bit difficult time to understand how this would not fail outside of tests.

Also you might consider for the fact that Boot creates SimpleJobExplorer automatically so this might be redundant, unless there a specific reason to create it manually.