* SPR-9594:
  Fix minor issue in MockHttpServletRequest

Previously MockHttpServletRequest#sendRedirect did not set the HTTP status
or the Location header. This does not conform to the HttpServletRequest
interface.

MockHttpServletRequest will now:

  - Set the HTTP status to 302 on sendRedirect
  - Set the Location header on sendRedirect
  - Ensure the Location header and getRedirectedUrl are kept in synch

Issue: SPR-9594

Update section on exception handling in Spring MVC chapter to include
more guidance on exception handling when implementing a REST API.

Issue: SPR-9290

Previously DefaultHandlerExceptionResolver did not handle BindException
but after this change it does. A BindException is raised when an
@ModelAttribute annotated argument is not followed by a BindingResult
argument. Hence this is unlikely to affect browser rendering.
For programmatic clients however this change ensures an unhandled
BindException is at least turned into a 400 error.

Issue: SPR-9310

The Atom/RSS message converters are now registered ahead of the
Jackson and the JAXB2 message converters by default. Since the Atom
and RSS converters convert to and from very specific object types
Feed and Channel respectively, that shouldn't introduce any regressions
and will work more intuitively when the requested media type is "*/*".

Issue: SPR-9054

* SPR-9576:
  Include **/*.aj files in *-sources.jar files

Previously only **/*.java sources files were included in the sources
jars. This is not ideal for the spring-aspects jar nor does it match
prior versions of the sources jars.

Now **/*.aj files are included in addition to the **/*.java files.

Issue: SPR-9576

Issue: SPR-9112

Before this change @ExceptionHandler methods could be located in and
apply locally within a controller. The change makes it possible to have
such methods applicable globally regardless of the controller that
raised the exception.

The easiest way to do that is to add them to a class annotated with
`@ExceptionResolver`, a new annotation that is also an `@Component`
annotation (and therefore works with component scanning). It is also
possible to register classes containing `@ExceptionHandler` methods
directly with the ExceptionHandlerExceptionResolver.

When multiple `@ExceptionResolver` classes are detected, or registered
directly, the order in which they're used depends on the the `@order`
annotation (if present) or on the value of the order field (if the
Ordered interface is implemented).

Issue: SPR-9112

Issue: SPR-9480

 Issue: SPR-9487

Prior to this change, PropertySourcesPropertyResolver (and therefore
all AbstractEnvironment) implementations failed to resolve nested
placeholders as in the following example:

    p1=v1
    p2=v2
    p3=${v1}:{$v2}

Calls to PropertySource#getProperty for keys 'p1' and 'v1' would
successfully return their respective values, but for 'p3' the return
value would be the unresolved placeholders. This behavior is
inconsistent with that of PropertyPlaceholderConfigurer.

PropertySourcesPropertyResolver #getProperty variants now resolve any
nested placeholders recursively, throwing IllegalArgumentException for
any unresolvable placeholders (as is the default behavior for
PropertyPlaceholderConfigurer). See SPR-9569 for an enhancement that
will intoduce an 'ignoreUnresolvablePlaceholders' switch to make this
behavior configurable.

This commit also improves error output in
PropertyPlaceholderHelper#parseStringValue by including the original
string in which an unresolvable placeholder was found.

Issue: SPR-9473, SPR-9569

Before this change HandlerMethod used ClassUtils.getUserClass(Class<?>)
to get the real user class, and not one generated by CGlib. However it
failed to that under all circumstances. This change fixes that.

Issue: SPR-9490

Before this change the StringHttpMessageConverter used a fixed charset
"ISO-8859-1" if the requested content type did not specify one. This
change adds a defaultCharset field and a constructor to configure it in
StringHttpMessageConverter.

Issue: SPR-9487

Issue: SPR-9287

moved getInputStream() not-null requirement to InputStreamSource itself; removed misleading "throws IllegalStateException" declaration

Issue: SPR-9561

Issue: SPR-9521

Issue: SPR-9528

Issue: SPR-9536

Before this change the HandlerExecitionChain logged errors each time a
an AsyncHandlerInterceptor returned a null async Callable, a condition
which is acceptable.

SPR-9524

* SPR-9530:
  Improve SimpleStreamingClientHttpRequest performance

Ensure that NonClosingOutputStream calls with a byte array call the
corresponding methods of the underlying OutputStream rather than
relying on the default NonClosingOutputStream implementation, which
writes one bte at a time. This significantly improves performance.

Issues: SPR-9530

Issue: SPR-9443, SPR-6847, SPR-9446, SPR-9444, SPR-9439, SPR-9302,
       SPR-9507, SPR-9238, SPR-9397, SPR-9406, SPR-9502

@Async executor qualification has been backported to 3.1.2. This commit
updates all @since tags appropriately, as well as carrying over the
changes backported to the spring-task-3.1 schema.

Issue: SPR-6847, SPR-9443

Issue: SPR-9289

Return an empty map when there are no path variables, rather than
raising an exception. This is consistent with similar resolvers for
extracting headers and request parameters.

Issue: SPR-9289

Following the introduction of ContentNegotiationManager that allows,
among other things, to configure the file extensions to use for content
negotiation, this change adds "smart" suffix pattern match that matches
against the configured file extensions only rather than against any
extension.

Given the request mapping "/jobs/{jobName}" and one configured file
extension ("json"), a request for "/jobs/my.job" will select the
pattern "/jobs/{jobName}" while a request for "/jobs/my.job.json" will
select the pattern "/jobs/{jobName}.json". Previously, both requests
would have resulted in the pattern "/jobs/{jobName}.*".

Issue: SPR-7632, SPR-8474

Issue: SPR-8410, SPR-8417, SPR-8418,SPR-8416, SPR-8419,SPR-7722

Issue: SPR-7985

The exact text above the "Staying in touch" section caused "Staying in
touch" to lose it's formatting as a second-level heading.  Adding
" for details" to the sentence above works around the problem.

Issue: SPR-9536

XStreamMarshaller should convert XStream StreamException to Spring
exception in case of unmarshalling an empty stream.

Issue: SPR-9536

The HTTP PATCH method is now supported whereever HTTP methods are used.
Annotated controllers can be mapped to RequestMethod.PATCH.

On the client side the RestTemplate execute(..) and exchange(..)
methods can be used with HttpMethod.PATCH. In terms of HTTP client
libraries, Apache HttpComponents HttpClient version 4.2 or later is
required (see HTTPCLIENT-1191). The JDK HttpURLConnection does not
support the HTTP PATCH method.

Issue: SPR-7985

Introduced ContentNeogtiationStrategy for resolving the requested
media types from an incoming request. The available implementations
are based on path extension, request parameter, 'Accept' header,
and a fixed default content type. The logic for these implementations
is based on equivalent options, previously available only in the
ContentNegotiatingViewResolver.

Also in this commit is ContentNegotiationManager, the central class to
use when configuring content negotiation options. It accepts one or
more ContentNeogtiationStrategy instances and delegates to them.

The ContentNeogiationManager can now be used to configure the
following classes:

- RequestMappingHandlerMappingm
- RequestMappingHandlerAdapter
- ExceptionHandlerExceptionResolver
- ContentNegotiatingViewResolver

Issue: SPR-8410, SPR-8417, SPR-8418,SPR-8416, SPR-8419,SPR-7722

PropertySourcesPropertyResolver#containsProperty now
calls #containsProperty on each underlying PropertySource instead of
calling #getProperty and checking for null.

Issue: SPR-9529

The reference manual currently documents the wrong file name for the
default data SQL script used by EmbeddedDatabaseBuilder. In addition,
the testing chapter of the reference manual does not link to the testing
section of the JDBC chapter.

 - Updated the "Testing data access logic with an embedded database"
   section of the reference manual appropriately.
 - Added a new paragraph to the "JDBC Testing Support" section of the
   testing chapter which cross references the "Testing data access logic
   with an embedded database" section.

Issue: SPR-9467