AnnotationUtils defensively catches and logs unexpected exceptions from retrieval attempts (proceeding like the annotation wasn't there)

Issue: SPR-11874
Consistent declaration of private static final logger variables

Issue: SPR-11905
Refactor VersionResourceResolver in strategies

Prior to this commit, one of the available strategies for resolving
resources was the PrefixResourceResolver. Reconsidering the core goal of
this resolver and the FingerprintResourceResolver, we found that the
true core feature is versioning static resources application-wide.

This commit refactors both Resolvers by:
* having only on VersionResourceResolver
* that resolver takes a mapping of paths -> VersionStrategy
* provided VersionStrategy implementations are ContentBasedVS
  (previously FingerprintRR), FixedVS (previously PrefixRR)

One can add a VersionResourceResolver like this:

  Map<String, VersionStrategy> versionStrategies = new HashMap<>();
  versionStrategies.put("/**/*.js", new PrefixVersionStrategy("prefix"));
  versionStrategies.put("/**", new ContentBasedVersionStrategy());

  VersionResourceResolver versionResolver = new VersionResourceResolver();
  versionResolver.setVersionStrategyMap(versionStrategies);

  List<ResourceResolver> resolvers = new ArrayList<ResourceResolver>();
  resolvers.add(versionResolver);
  resolvers.add(new PathResourceResolver());

Issue: SPR-11871
Preparations for eventual removal of ParameterizedRowMapper along with SimpleJdbcTemplate

Issue: SPR-11895
TypeDescriptor's nested type traversal leniently returns null in case of unresolvable nested type

Issue: SPR-11898
Avoid pattern matching in isCglibRenamedMethod as far as possible (for performance reasons)

Issue: SPR-11894
FrameworkPortlet exposes local PortletRequestAttributes in case of pre-bound ServletRequestAttributes as well

Issue: SPR-11295
Require JUnit 4.9 or higher in the TCF

Prior to this commit, the Spring TestContext Framework (TCF) was
compatible with JUnit 4.5 or higher.

This commit effectively raises the minimum version of JUnit that is
officially supported by the TCF to JUnit 4.9, thereby aligning with
similar upgrades made in the Spring Framework 4.0 release (i.e.,
upgrading minimum requirements on third-party libraries to versions
released mid 2010 or later).

Issue: SPR-11908
SelectTag consistently checks specified 'multiple' attribute now, never falling back to forceMultiple in case of user-provided value

Issue: SPR-11903
Explicitly mention BeanPostProcessor declaration requirements with @Bean methods

Issue: SPR-11906
UriComponentBuilder allows for multiple independent build() calls on same builder instance

Issue: SPR-11885
ConfigurationClassPostProcessor skips pre-processed bean definitions now (avoiding side effects in case of multiple CCPPs)

Issue: SPR-11858
Polish SockJsFrame
Add SockJsFrameType enum

SPR-10797
Support registering Filters in WebSocket test servers
Add SockJS client

This change adds a new implementation of WebSocketClient that can
connect to a SockJS server using one of the SockJS transports
"websocket", "xhr_streaming", or "xhr". From a client perspective
there is no implementation difference between "xhr_streaming" and
"xhr". Just keep receiving and when the response is complete,
start over. Other SockJS transports are browser specific
and therefore not relevant in Java ("eventsource", "htmlfile" or
iframe based variations).

The client loosely mimics the behavior of the JavaScript SockJS client.
First it sends an info request to find the server capabilities,
then it tries to connect with each configured transport, falling
back, or forcing a timeout and then falling back, until one of the
configured transports succeeds.

The WebSocketTransport can be configured with any Spring Framework
WebSocketClient implementation (currently JSR-356 or Jetty 9).

The XhrTransport currently has a RestTemplate-based and a Jetty
HttpClient-based implementations. To use those to simulate a large
number of users be sure to configure Jetty's HttpClient executor
and maxConnectionsPerDestination to high numbers. The same is true
for whichever underlying HTTP library is used with the RestTemplate
(e.g. maxConnPerRoute and maxConnTotal in Apache HttpComponents).

Issue: SPR-10797
Fix concurrency issues in SockJS session impls

This change ensures the server "WebSocketHandler" is notified of the
opening of a session before writing the open frame to the remote
handler. Any messages sent by the server "WebSocketHandler" while
getting notified of the opening get cached and flushed after the open
frame has been written.

This change introduces locking in AbtractHttpSockJsSession to guard
access to the HTTP response. The goal is to prevent contention between
client requests to receive messages (i.e. long polling) and
the application trying to write.

Issue: SPR-11916
Prevent unbounded retention of cancelled SockJS tasks

This change sets the removeOnCancelPolicy on the SockJS
ScheduledThreadPoolExecutor to true. This ensures that cancelled
tasks are removed immediately to avoid the "unbounded retention
of cancelled tasks" that is mentioned in the Javadoc of
ScheduledThreadPoolExecutor:

"By default, such a cancelled task is not automatically removed from
the work queue until its delay elapses. While this enables further
inspection and monitoring, it may also cause unbounded retention of
cancelled tasks. To avoid this, set setRemoveOnCancelPolicy to true,
which causes tasks to be immediately removed from the work queue at
time of cancellation."

Issue: SPR-11918
Use SimpleAsyncTaskExecutor in WebSocketClient impls

JettyWebsocketClient and StandardWebSocketClient now use the
SimpleAsyncTaskExecutor by default to ensure non-blocking connect.
Merge SockJS client-related changes