See gh-18631

Rename "app" projects in `spring-boot-launch-script-tests` and
`spring-boot-loader-tests` to something unique.

See gh-18631

Closes gh-24554

Update the jar `Handler` class to support a non-reflective fallback
mechanism when possible. The updated code attempts to capture a regular
jar URL before our handler is installed. It can then use that URL as
context when creating the a fallback URL. The JDK jar `Handler` will
be copied from the context URL to the fallback URL.

Without this commit, resolving new Tomcat URLs of the form
`jar:war:file:...` would result in an ugly "Illegal reflective access"
warning.

Fixes gh-18631

Update `StandardConfigDataResource`  to make the `getResource()` method
public so that it can be used by Spring Cloud.

Closes gh-24504

Refine the `PortInUseException` logic in `NettyWebServer` to only throw
an exception if the port is set. The prevents a misleading exception
from being thrown when a domain socket is being used.

Closes gh-24529

Update `NettyWebServer` to deal with any `UnsupportedOperationException`
thrown from `DisposableServer`. Specifically, this commit allows the
`NettyWebServer` to work with domain socket backed servers which cannot
provide a port.

Fixes gh-24529

See gh-11987

Closes gh-24542

Fixes gh-11987

Closes gh-24538

Fixes gh-24522

Closes gh-24536

* pr/24532:
  Avoid duplicates in MergedContextConfiguration

Closes gh-24532

Fixes gh-24521 in 2.4.2

Remove duplicate config attribute classes by using a `Set` rather
than a `List` in the `SpringBootTestContextBootstrapper`.

See gh-24532

Prior to this commit, running the bootBuildImage Gradle task on a
project configured for war packaging would result in a jar file being
built and used in the image instead of the war file. With this commit
an error will be thrown from the plugin in this case.

Fixes gh-24521

Closes gh-24526

Add an overloaded `ConfigDataEnvironmentPostProcessor.applyTo` method
that accepts a listener that can used to track the updates that were
applied to the `Environment`.

The listener can be used to track the which `ConfigDataLocation` and
the `ConfigDataResource` were used to add a `PropertySource`. The lister
can also be used to tell which profiles were applied.

This enhancement is being added in a patch release because it's will
be useful for Spring Cloud 2020.0.0.

Closes gh-24504

Add an additional test to ensure that empty property files do not
throw ConfigDataLocationNotFoundException exceptions.

See gh-24499
See gh-24515

Closes gh-24518

Closes gh-24486

Closes gh-24513

Closes gh-24472

Closes gh-24498

* pr/24477:
  Use BindResult.orElseGet() where beneficial

Closes gh-24477

See gh-24477

Allow directory locations that exist but do not contribute properties
to be specified without an `optional:` prefix. This commit fixes logic
introduced in commit 3dc03ac2 which didn't account for the fact that
a directory might contain only profile specific property files and that
profiles might not always be active.

Closes gh-24499

See gh-24501

Closes gh-24501

Closes gh-24500

Fixes gh-24475

Closes gh-24495

Closes gh-24494