Before this change, the type of asynchronously produced return values
(e.g. Callable, DeferredResult, ListenableFuture) could not be
properly determined with an actual resulting value of null. Or even
with an actual value returned, the generic type could not be properly
determined. This change fixes both of those issues.

Issue: SPR-12287

Prior to this commit, the cache operation metadata cache was not
updated for a method not using the JCache annotations. This means
that every execution of said method was going through the process
of identifying if it was using the cache or not.

This commit adds a default placeholder identifying the absence of
metadata; this allows to flag such method as not having any metadata
at all.

Issue: SPR-12337

The getForRequestUrl method of ResourceUrlProvider uses the
HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE attribute to
determine the relevant portion of the resource URL path.

However there are cases when that attribute may not have a leading
(e.g. when the current URL was matched to a prefix-based pattern
and hence extracted via PathMatcher#extractPathWithinPattern), which
interferes with the matching of resource URL paths to patterns.

This change ensures a leading slash is present

Issue: SPR-12281

Snake YAML allows for duplicate keys in map nodes. See
https://code.google.com/p/snakeyaml/issues/detail?id=199

This commit uses a dedicated Constructor extension that explicitly
checks for such duplicate keys.

Issue: SPR-12318

Use explicit flag whether to copy all attributes.

Issue: SPR-12319

Issue: SPR-12173

The resourceHandlerMapping in the MVC Java config is not configured
with any interceptors, and in particular those added through the
InterceptorRegistry, which are otherwise added to all other handler
mapping beans created by the config. This means that the
ResourceUrlProviderExposingInterceptor (added in 4.0) is also not
used for resource requests.

This change ensures the ResourceUrlProviderExposingInterceptor is
configured on the resourceHandlerMapping.

Issue: SPR-12279

Issue: SPR-12324

The WebSocketMessageBroker config now allows wrapping the
SubProtocolWebSocketHandler to enable advanced use cases that may
require access to the underlying WebSocketSession.

Issue: SPR-12314

Issue: SPR-12314

Issue: SPR-12301

This change adds a new XhrTransport for the SockJs client
implementation. This transport is based on `UndertowClient`,
Undertow's HTTP client.

Note that this transport can be customized with an OptionMap that is
used by the Xnio worker backing the I/O communications (see
http://xnio.jboss.org).

Implementation tested with undertow 1.0.36, 1.1.0.RC3, 1.2.0.Beta1.

Issue: SPR-12008

This change adds a "Vary: Origin" HTTP response header for /info and
/iframe SockJS endpoints.
This is preventing proxies and browsers from caching a response and
reusing it for an invalid Origin.

Reference: https://groups.google.com/forum/#!topic/sockjs/svsLWRorSis

Issue: SPR-12310

Issue: SPR-12313

This commit adds support for direct Jackson mix-in annotations registration in
Jackson2ObjectMapperFactoryBean and Jackson2ObjectMapperBuilder.

Issue: SPR-12144

Issue: SPR-12308

Issue: SPR-12311

TextMessage.toString() does not throw StringIndexOutOfBoundsException for payload with multibyte characters

Issue: SPR-12307

Issue: SPR-12306

Comprehensive revision of SpEL's bytecode generation and number handling (BigInteger support, doubleValue fallback)

Issue: SPR-9913

Issue: SPR-12280

Issue: SPR-12299

Issue: SPR-12297

Issue: SPR-12250

JavaMailSenderImpl catches Exception instead of MessagingException and checks for reconnect in case of message batches

Issue: SPR-12298

This commit changes email addresses and URLs so that they point to
pivotal.io instead of gopivotal.com.

Also includes varargs declaration for applicable send methods.

Issue: SPR-12294

AbstractMessageChannel triggers afterSendCompletion with previously resolved non-null Message in case of preSend returning null

Issue: SPR-12295