Prior to this commit, finding out how many application contexts had
been loaded within a test suite required the use of reflection and a
bit of hacking.

This commit addresses this issue by logging ContextCache statistics
whenever an application context is loaded by the Spring TestContext
Framework (TCF).

The log output can be enabled by setting the
"org.springframework.test.context.cache" logging category to DEBUG.

Issue: SPR-12409

This commit updates the documentation of the task:executor element to
reference the keep-alive flag.

Issue: SPR-12407

Prior to this change, duplicate SubProtocolHandlers could be registered
when configuring STOMP with several registrations:

    public void registerStompEndpoints
          (final StompEndpointRegistry registry) {
      this.endpointRegistry.addEndpoint("/stompOverWebSocket");
      this.endpointRegistry.addEndpoint("/stompOverSockJS").withSockJS();
    }

This commit registers sub-protocols in a Set instead of a list (see
SubProtocolWebSocketHandler), thus fixing the issue.

Issue: SPR-12403

As indicated by our recent Spring Integration test failure, autowiring attempts after context closing did not fail before. After the introduction of the separately managed manualSingletonNames set, the algorithm could run into a situation where a singleton name is still in the manualSingletonNames set but not in the singletonObjects map anymore. As a remedy, destroySingletons needs to explicitly clear the manualSingletonNames set in order to remove references to non-disposable singleton beans as well (which are otherwise left in the set since individual destroySingleton calls only come in for disposable beans with destroy methods).

Issue: SPR-12404

(cherry picked from commit acefd838)

Issue: SPR-9735
(cherry picked from commit 7fa3e65d)

Defensive handling of manually registered singleton names (based on Spring Integration test failure)

Issue: SPR-12404

Issue: SPR-12405

DefaultListableBeanFactory efficiently accesses current bean names and exposes them via getBeanNamesIterator()

Issue: SPR-12404

Issue: SPR-12336

Issue: SPR-12336

Issue: SPR-12374

BeanDefinitionValueResolver preserves original String array if possible and resolves nested String arrays as well

Issue: SPR-12391

ScheduledAnnotationBeanPostProcessor uses getBean(Class) for TaskScheduler/ScheduledExecutorService retrieval, allowing for a scheduler bean to be flagged as primary, and for a TaskScheduler bean to override a ScheduledExecutorService bean.

ContextLifecycleScheduledTaskRegistrar hooks into SmartInitializingSingleton's afterSingletonsInstantiated callback instead of ContextRefreshedEvent, as a natural consequence of SmartInitializingSingleton's introduction in Spring Framework 4.1 GA.

Unit tests for java.util.Optional with autowired collections on @Autowired fields/methods and @Bean method parameters

Issue: SPR-9132

Issue: SPR-12401

Prior to this commmit, any configuration class holding a CacheManager
bean would be eagerly instantiated. This is because the
CacheConfiguration infrastructure requests all beans of type
CacheManager.

This commit defers the resolution of the CacheManager as late
as possible.

Issue: SPR-12336

This commit adds an explicit support for String array for value
resolution. <util:properties> switches the 'locations' property to a
String array in 662d8aa9 and this broke expression evaluation.

Issue: SPR-12391

Reintroduced original SpringSessionSynchronization constructor and made SpringSession/FlushSynchronization public (for GORM)

Issue: SPR-12400

Issue: SPR-12399

Issue: SPR-12397

Issue: SPR-12398

Issue: SPR-12396

Issue: SPR-12396

Class-level Javadoc for MockHttpServletRequestBuilder now correctly
refers to MockMvcRequestBuilders instead of MockMvcBuilders.

Issue: SPR-12393

Issue: SPR-10397

Issue: SPR-12394

SimpleMetadataReaderFactory is capable of resolving inner class names with dot syntax now (analogous to ClassUtils.forName)

Issue: SPR-12390