Closes gh-23870

See gh-23870

Closes gh-23780

Closes gh-23777

See gh-23803

Make use of the new getAvailableExtensionNames() method.

Closes gh-23799

See gh-23638

See gh-23534

Upgrade to SLF4J 1.7.28, Groovy 2.5.8, RxJava 2.2.12, Joda-Time 2.10.4, Rome 1.12.2, OkHttp 3.14.3, Apache HttpClient 4.5.10, Apache Johnzon 1.1.13

Bypass server cookie and write Set-Cookie header directly for Reactor
Netty, and Servlet API which do not provide options.

For Undertow use the sameSite attribute.

Closes gh-23693

Includes Netty 4.1.39 (aligned with Reactor) and Checkstyle 8.24.

Closes gh-23641

Closes gh-23635

Also restores immediate MethodOverrides instance in AbstractBeanDefinition, avoiding potential lazy-init race condition.

Closes gh-23448

Closes gh-23593

Closes gh-23694

Closes gh-23630

Closes gh-23534

Closes gh-23313

If an error looks like a "disconnected client" but the response is not
yet committed then it can't be an I/O error from writing to the server
response. It is most likely as a result of a remote call as part of
request handling.

Not setting the response to 500 in this case results in a 200 response
status despite the error. Even if it was an I/O error from the server
response, setting the status won't impact a failed response.

Closes gh-23319

While resolving the regression raised in gh-23571, it came to our
attention that not all of our ClassFilter and MethodMatcher
implementations were properly cacheable with CGLIB generated proxies
due to missing (or improper) equals() and hashCode() implementations.

Although such deficiencies may not manifest themselves as bugs in Core
Spring's default arrangements, these might cause issues in custom
arrangements in user applications.

This commit addresses this by ensuring that ClassFilter and
MethodMatcher implementations properly implement equals() and
hashCode(). In addition, missing toString() implementations have been
added to improve diagnostics for logging and debugging.

Closes gh-23659

Prior to this commit, concurrent invocations of
DefaultListableBeanFactory.removeBeanDefinition() could result in a
NullPointerException.

This commit fixes this by adding an appropriate not-null check in
resetBeanDefinition().

Closes gh-23542

Fixes gh-23631

This commit makes sure that DefaultResourceLoader consistently use
getProtocolResolvers() to access additional protocol resolvers. This
allows subclasses to define how the list is provided.

Closes gh-23564

Update the checkstyle rule to enforce the blank line between `java`
and `javax`.

See gh-23539

See gh-23539
Co-authored-by: NSam Brannen <sbrannen@pivotal.io>

See gh-23093
Co-authored-by: NSebastien Deleuze <sdeleuze@pivotal.io>

Closes gh-22926

See gh-22821

See gh-22821

Ensure that results returned from keySet, entrySet & values are tracked
to remove case insensitive keys from the source map.

Closes gh-22821

See gh-22821

See: gh-23553

On a Servlet container a completion notification may come at any time
even in the UNSUBSCRIBED state, i.e. before the write Publisher has
called onSubscribe.

See: gh-23553