Constructor calls like new AtomicInteger(0) cause a volatile write that
can be saved in cases where the constructor parameter is the default
value.

See gh-23575

* pr/23041:
  Polish "Improve Cassandra health indicator with more robust mechanism"
  Improve Cassandra health indicator with more robust mechanism

Closes gh-23041

See gh-23041

See gh-23041

* pr/23554:
  Improve performance of DispatcherServletRegistrationCondition

Closes gh-23554

See gh-23554

* pr/23564:
  Polish "Add configuration option for channelRpcTimeout"
  Add configuration option for channelRpcTimeout

Closes gh-23564

See gh-23564

This commit adds a configuration option to configure
RabbitConnectionFactory's channelRpcTimeout property.

See gh-23564

* pr/23571:
  Update copyright of changed file
  Use platform-independent line separator

Closes gh-23571

See gh-23571

See gh-23571

Closes gh-23573

* pr/23561:
  Fix typos

Closes gh-23561

See gh-23561

Closes gh-23570

Closes gh-23569

* pr/23566:
  Polish "Do not fail if h2Console bean cannot connect to db"
  Do not fail if h2Console bean cannot connect to db

Closes gh-23566

See gh-23566

See gh-23566

Closes gh-23568

Closes gh-23567

* pr/23562:
  Remove documentation for unsupported gradle versions

Closes gh-23562

See gh-23562

* pr/23565:
  Polish "Deprecate EmbeddedDatabaseConnection#HSQL"
  Deprecate EmbeddedDatabaseConnection#HSQL in favor of HSQLDB

Closes gh-23565

See gh-23565

See gh-23565

Closes gh-23557

Closes gh-23555

Previously, JettyEmbeddedErrorHandler would change the method of every
request that is handles to GET. This was being done to work around
Jetty's error handling only dealing with GET, POST, and HEAD requests
by default. It had the unwanted side-effect of causing an error
response to a HEAD request having a body as, from the error handling's
perspective, it was a GET request.

This commit updates JettyEmbeddedErrorHandler to only set the method
on a request for which error handling is being performed if the method
isn't already one that will be handled, leaving the method of GET,
POST, and HEAD requests unchanged.

Unfortunately, short of implementing an HTTP client, this change cannot
be tested as the Apache HttpClient, OkHttp, and the JDK's
HttpURLConnection all silently drop the body of a response to a HEAD
request, preventing a test from asserting that a body hasn't been sent.

Closes gh-23551

Closes gh-23547

Closes gh-23548

Closes gh-23549

Closes gh-23546