Closes gh-4719

Update the documentation to include a section about ServletContext
initialization with embedded servlet containers. This update is to
primarily highlight that `WebApplicationInitializers` and Servlet 3.0+
`ServletContainerInitializers` are not called.

Fixes gh-4643

If the user provides their own ServerProperties bean we want to peek
at it to see if they set the port (and only that) when we are deciding
if the actuator context needs to be created. This happens very early
(in a @Condition) so we need to be very defensive. There are already
quite a few checks in place to prevent a ServerProperties bean from
being instantiated unless we really need it, and yet, when it is
we can do more.

This change creates the bean (and the ManagementProperties) in a
throwaway BeanFactory using the same BeanDefinition as the main
context. This ensures that when the main context bean is created
it will be in the "natural" order and binding to the Environment
can take place as normal.

Fixes gh-4631

Closes gh-4790

Closes gh-4791

Closes gh-4789

The issue with Spring Data Gemfire has been resolved [1]

See gh-4786

[1] https://github.com/spring-projects/spring-data-gemfire/commit/34665d16ec543e85afcde174194ba5fbff44b841

* gh-4506:
  Update launch.script to append to $log_file rather than overwriting it

Closes gh-4506

See gh-4786

Exiting with 0 when cd fails is likely to be incorrectly interpreted
as success so we should exit with a non-zero value. Ideally, the init
script status action would exit with 4 but, at the point when
the cd is performed, we don’t even know if we’re running as an init
script. Exiting with 1 seems to be a reasonable compromise as it’s
fine for the non init-script case as well as being correct for all
init script actions other than status.

See gh-4653

Closes gh-4653

See gh-4163

Spring Data’s web support includes a handler method argument resolver,
ProxyingHandlerMethodArgumentResolver, that inaccurately claims that it
can handle all interface handler method arguments. This causes problems
for handler methods that take Spring Mobile’s Device as an argument as
the proxied Device instance does not behave correctly.

This commit works around the problem by assigning an order to the 
WebMvcConfigurerAdapter that registers Spring Mobile’s argument resolver
with Spring MVC. This ordering ensures that Spring Mobile’s resolver
takes precedence over Spring Data’s for Device arguments.

Closes gh-4163

This change permanently removes links from the endpoints that return
arrays or collections, and also disables them in the rest of the
endpoints (except /actuator) by default.

Fixes gh-4616

Closes gh-4597

* pr/4686:
  Log exception before sending to listeners

Change SpringApplication exception handling to log details before calling
the SpringApplicationRunListeners. Prior to this commit it wasn't possible
for a listener to shutdown logging.

Fixes gh-4680
Closes gh-4686

* pr/4780:
  Fix mail connection test exception message

Closes gh-4780

Allow users to easily opt-opt of using the start-stop-daemon in the
launch script. This may be required on distros that include older
versions.

Fixes gh-4732

* pr/3847:
  Auto-configure Elasticsearch converter and context

Extend ElasticsearchDataAutoConfiguration to also configure an
ElasticsearchConverter and SimpleElasticsearchMappingContext both
of which are required for Spring Data REST.

Closes gh-3847

See gh-4765
See gh-4766

* pr/4760:
  Upgrade to maven-invoker-plugin 1.10

Closes gh-4760

Google App Engine probits the creation of new threads. This leads to a
failure in BackgroundPreinitializer when the single thread executor
attempts to create its single thread.

This commit enhances the existing fail safety of
BackgroundPreinitializer by catching any exceptions thrown while
creating the executor and submitting the tasks to it. Any initialisation
that has not performed in the background will be performed in the
foreground instead.

Closes gh-4662

* pr/4766:
  Use canonical paths for Undertow document root

Update `UndertowEmbeddedServletContainerFactory` so that the canonical
path is used when setting up the document root. Prior to this commit
Windows machines with `java.io.tmpdir` set to a tilde-compressed path
would cause problems.

Fixes gh-4765
Closes gh-4766

Previously, the default RestTemplate that is used OpenTsdbGaugeWriter
was not used with its default configuration. Notably this meant that
it would have infinite connect and read timeouts. This is problematic
as it can cause metric writing to hang and block the scheduler for
performing any other tasks.

This commit updates OpenTsdbGaugeWriter to use a default connect
timeout of 10 seconds and a default read timeout of 30 seconds. A
constructor has been added to ease the configuration of these
timeouts. The existing option of providing your own RestTemplate
(via setRestTemplate) remains.

Closes gh-4698

Closes gh-4731

- Consistent error handling applied to BasicJsonParser,
  GsonJsonParser, JsonSimpleJsonParser and YamlJsonParser
- Add tests in AbstractJsonParserTests to verify consistency
- Rename tests for JsonSimpleJsonParser to match the name of the
  class under test.

Closes gh-4690

Previously, when ignoreUnknownFields was false and property names were
being filtered based on whether or not they begin with the target name,
relaxed variants of the target name were not considered. This resulted
in different delimiters resulting in a non-match. For example, the
property ENV_FOO_NAME would be filtered out when the target name
was env.foo.

This commit updates PropertiesConfigurationFactory to pass all of the
relaxed variants for the target name to the matcher. For the example
above one of those variants will be env_foo which matches ENV_FOO_NAME
due to the matching delimiter.

PropertiesConfigurationFactory was already creating a RelaxedNames
instance for the target name. The code has been reworked a little to
allow these relaxed names to be reused, thereby avoiding the cost of
computing all of the relaxed variants of the target name a second time.

Closes gh-4775

Update ConfigurationWarningsApplicationContextInitializer to also log
warnings if the user is scanning `org` or `org.springframework`.

Fixes gh-4777

Closes gh-4776