Lookup available JobRegistry from context for JobOperatorFactoryBean

[quaff]

No description provided.

[fmbenhassine]

Thank you for the PR! However, as mentioned in #5229 (comment) , this introduces a breaking change and is not consistent with how other optional components are customized (why would we use an ObjectProvider for the registry but not the for task executor or the job parameters converter?)

The way to fix the issue is by looking for a registry from the context before creating a default one (similar to what we do for the datasource and the transaction manager in the JDBC config. Can you please update the PR accordingly? Thank you upfront.

As a side note, regarding spring-projects/spring-boot#48992 (comment), this is not an oversight. The class is designed to accept mandatory dependencies as constructor parameters, while optional dependencies can be customized by overriding getters (the registry is optional starting from v6).

[quaff]

Updated.

[quaff]

Another question, is registry job the responsibility of JobRegistry implementation or DefaultBatchConfiguration ?

I suggest latter, and remove logic from MapJobRegistry:

spring-batch/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapJobRegistry.java

Lines 64 to 74 in a3a517f

	public void afterSingletonsInstantiated() {
	Map<String, Job> jobBeans = this.applicationContext.getBeansOfType(Job.class);
	for (Job job : jobBeans.values()) {
	try {
	register(job);
	}
	catch (DuplicateJobException e) {
	throw new IllegalStateException("Unable to register job " + job.getName(), e);
	}
	}
	}