revised Servlet 3.0 based StandardServletMultipartResolver for correct param/file distinction; added multipart content type and headers access to MultipartRequest (dropping the previous header access solution on MultipartFile); MultipartFilter uses a Servlet 3.0 based StandardServletMultipartResolver by default

SPR-8001 Recognize case when MultipartRequest is null and argument is of type MultipartFile and raise helpful exception.

SPR-8532 Upgrade org.springframework.web.servlet to Servlet 3.0 (as provided dependency) and add support for javax.servlet.Part parameter

Move JNDI_PROPERTY_SOURCE_ENABLED_FLAG from JndiPropertySource to
StandardServletEnvironment, as this is the only context in which the
constant makes sense.

Issue: SPR-8496

SPR-8447 Provide sufficient contextwherever possible when exceptions are raised in new @mvc classes.

SPR-8487 Ensure setters for argument resolvers and return value handlers replace the defaults completely.

SPR-8476 Translate JsonMappingExceptions to HttpMessageNotReadableException (and thus response status code 400) consistent with JsonParseExceptions

Per review with Juergen in light of SPR-8413, which will revisit the
overall structure of ACAC and ACWAC.

Issue: SPR-8365, SPR-8413

Issue: SPR-7672

Issue: SPR-7672

Constructors have been added to both ContextLoader and
ContextLoaderListener to support instance-based programmatic
registration of listeners within ServletContainerInitializer
implementations in Servlet 3.0+ environments, and more particularly
when using Spring 3.1's WebApplicationInitializer SPI.

Issue: SPR-7672

ContextLoader and FrameworkServlet now use
AnnotationAwareOrderComparator to support @order usage; previously
supported only implementation of the Ordered interface.

GenericWebApplicationContext now implements
ConfigurableWebApplicationContext in order to be compatible with
Framework/DispatcherServlet and ContextLoader/Listener, especially with
regard to changes in SPR-7672 that allow for programmatic use of these
types within Servlet 3.0+ environments.  For the first time, it's now
reasonable to imagine injecting a GWAC into DispatcherServlet; the most
robust way to accommodate this possibility is for GWAC to implement
CWAC.

The implementation is in name only, allowing for interchangable use of
GWAC anywhere, for example, an XWAC could otherwise go.  Methods such
as setConfigLocation will throw UnsupportedOperationException if the
configLocation value actually contains text.  Other methods are
implemented as no-ops or to throw UOE as appropriate.

Issue: SPR-7672

WebApplicationInitializer provides a programmatic alternative to the
traditional WEB-INF/web.xml servlet container deployment descriptor
for Servlet API 3.0+ environments.

This is done by building atop the new ServletContainerInitializer
support in Servlet 3.0. See SpringServletContainerInitializer for
complete details. And see WebApplicationInitializer Javadoc for
typical usage examples.

Issue: SPR-7672

AnnotationConfigApplicationContext and
AnnotationConfigWebApplicationContext both expose #register and #scan
methods as of the completion of SPR-8320. This change introduces a new
interface that declares each of these methods and refactors ACAC and
ACWAC to implement it.

Beyond information value, this is useful for implementors of the
ApplicationContextInitializer interface, in that users may create an ACI
that works consistently across ACAC and ACWAC for standalone (e.g.
testing, batch) or web (e.g. production) use.

Issue: SPR-8365,SPR-8320