Polish Javadoc for @JmsListener
Polish Javadoc for BackOff implementations
Restore sleep interval between recovery attempt

Commit 6a04831 introduced a regression that lead to burst recovery
attempts when the broker is up but the listener is failing for some
reason (the most obvious one being that the destination does not
exist).

Since the sleep period between recovery attempts strategy is more
complex, we can't just sleep for a period of time. But we can create
an execution and apply it once which should work just fine for most
use cases.

Issue: SPR-12183
MethodReference accesses cached executor in a thread-safe manner

Issue: SPR-12269
Polishing
FormHttpMessageConverter uses a delegate class for JavaMail-based MIME encoding (isolating the JavaMail API dependency)

Issue: SPR-12108
JsonViewResponseBodyAdvice throws IllegalArgumentException in case of >1 view class specified

Issue: SPR-12270
Update default view resolver in MVC Java config

When not ViewResolver's have been registered, detect if the context
contains any other ViewResolver beans. If not, add InternalResourceVR
to match default DispatcherServlet behavior.

Issue: SPR-12267
Polishing
Correct check for ViewResolver beans

Check for bean names of type rather than actual beans.

Issue: SPR-12267
Polish ExecutorSubscribableChannel

Consolidate inner classes used to invoke a subscriber with
interceptors.
Add MessageHandlingRunnable

Issue: SPR-12272
Allow configuring custom ThreadPoolTaskExecutor

Issue: SPR-12272
Create a builder for Jackson ObjectMapper

Jackson2ObjectMapperBuilder now allows to create ObjectMapper and XmlMapper
instances easily thanks to its fluent API.

This builder is used in Jackson message converters and views to instantiate default
ObjectMapper and XmlMapper.

This commit also add a createXmlMapper property to
Jackson2ObjectMapperFactoryBean in order to allow to create easily a XmlMapper
instance.

Issue: SPR-12243
Set Jackson FAIL_ON_UNKNOWN_PROPERTIES property to false by default

Issue: SPR-11891
Set Jackson DEFAULT_VIEW_INCLUSION property to false by default

Issue: SPR-12179
Improve @JsonView reference documentation

Issue: SPR-12270
Fix condition vs. conditional typo in documenation

Issue: SPR-12273
Merge pull request #654 from adjohnson916/SPR-12273

* SPR-12273:
  Fix condition vs. conditional typo in documenation
MethodReference accesses cached executor in a thread-safe manner

Issue: SPR-12269