Closes gh-5013

Closes gh-4955

Since 2.2.5 hasn't yet been released we'll need to rollback for our
release.

See gh-4789

Update the ContextIdApplicationContextInitializer default NAME_PATTERN
to favor the developer defined `${spring.application.name}` value over
the deployer defined `${vcap.application.name}`.

Fixes gh-4926

Update TomcatEmbeddedServletContainerFactory so that logic to disable
persistent sessions happens after Tomcat's standard Manager creation
logic.

Fixes gh-4543

Update `ResourceBundleCondition` to only enable the messages source
if `messages.properties` (and not `messages*.properties`) exists. This
operation is much faster that performing a pattern match since a full
jar entry scan is not required.

Since adding `messages.properties` is good practice and this change
allows us to delete the custom `PathMatchingResourcePatternResolver`
it seems like a fine compromise to make.

Fixes gh-4930
See gh-4811

Closes gh-5003

Closes gh-5002

Closes gh-5001

Closes gh-5000

Closes gh-4999

Closes gh-4998

Closes gh-4997

Closes gh-4996

Now tracked by gh-4995

Closes gh-4978

Commit 5a1ee6eb added support for disabling use of start-stop-daemon
via a placeholder in the default launch script. Unfortunately, that
placeholder was subsequently broken in 81a47639.

This commit reinstates the placeholder and adds tests to verify that all
of the placeholders in the launch script can be replaced and that they
have the required default values. Furthermore, it also allows the use of
start-stop-daemon to be configured via USE_START_STOP_DAEMON in an
app’s .conf file. This allows the configuration to be changed after the
app has been built.

Closes gh-4985

Closes gh-4973

This commit allows to use the `flyway.locations` in an indexed fashion
(i.e. typically in YAML configuration).

See gh-4973

When a Jersey app is deployed to a standalone container, Jersey’s
ServletContainerInitializer will run and register a servlet for a class
annotated with @ApplicationPath. If Jersey’s ServletContainerInitializer
runs before Spring’s, this servlet will take precedence over the
servlet registered by JerseyAutoConfiguration and will therefore not be
configured with any init parameters specified using spring.jersey.init

For the case where Jersey’s SCI runs first, this commit updates
JerseyAutoConfiguration to examine the servlet context for an existing
registration of Jersey’s servlet (Jersey names the registration using
the fully-qualified name of the ResourceConfig subclass). If a
registration is found its init parameters are configured using the
configuration provided by spring.jersey.init.

For the case where Spring’s SCI runs first, this commit updates
JerseyAutoConfiguration so that it names its registration using the
fully-qualified name of the ResourceConfig sub-class. This allows
Jersey’s SCI to find the existing registration rather than attempting
to configure its own.

Closes gh-2471

* gh-4801:
  Add mainApplicationClass accessor to SpringApplication

Closes gh-4801

If application context refresh fails, SpringApplication will have a 
null context. Previously, this would result in an NPE when looking for
an ExitCodeExceptionMapper.

This commit updates SpringApplication to gracefully handle the context
being null when looking for an ExitCodeExceptionMapper.

Closes gh-4803

Closes gh-4971

Previously, if an application’s main method threw an exception,
MainMethodRunner would catch the exception and call System.exit(1).
This meant that the JVM would exit, irrespective of whether or not
any non-daemon threads were running. In contrast, when an application’s
main method was invoked directly (in an IDE, for example) the JVM
would not exit if one or more non-daemon threads were running. This
is standard JVM behaviour that we should be consistent with in the
launcher.

This commit updates MainMethodRunner to wrap any exception thrown by an
application’s main method in a RuntimeException and rethrow it. This
alllows the JVM to handle the exception and use its normal rules for
deciding whether or not it should exit.

Closes gh-4984

* pr/4987:
  Update inconsistent documentation

Closes gh-4987

While Flyway's `MigrationVersion` is a String value, a simple "0" is
also a valid number. When such value is not wrapped in YAML, an integer
is injected rather than a String which leads to a failure as we can't
convert it.

This commit updates the `StringToMigrationVersionConverter` to also
supports conversion from a Number. This is a convenience for users
using YAML for configuration

Closes gh-4981

This commit makes sure to also include any `GenericConverter` flagged for
inclusion in the conversion service to use to convert configuration keys.

Previously, those were ignored as `Converter` and `GenericConverter` are
two separate interfaces.

Closes gh-4988

The same initializer will receive multiple ContextRefreshedEvents
when their is an application context hierarchy. This commit updates
the initializer to correctly handle multiple ContextRefreshedEvents
and only act upon the first that it receives.

See gh-4871