* pr/18918:
  Polish

Closes gh-18918

See gh-18918

Previously, our Gradle plugin was not tested against Gradle 6.0,
a number of deprecation warnings were output when using the plugin
with Gradle 6, and some functionality related to the application
plugin did not work as expected.

This commit tests the plugin against Gradle 6. It also avoids calling
deprecated APIs. The plugin is compatibile against Gradle 4.10 where
the deprecated APIs' replacements are not available so reflection is
used to call the replcaements. Lastly, the way in which the base name
of the boot distribution that is created when the application plugin
is applied has been modified to ensure that it is effective when using
Gradle 6.

Closes gh-18663

Fixes gh-18904

Closes gh-18943

Closes gh-18842

Closes gh-18940

Previously, when RunProcess handled a SIGINT it would immediately
attempt to destroy the process that it had run. This created a race
condition between the SIGINT being handled by the child process
and RunProcess destroying the child. The exact behavior of destroy
is implementation dependent and it may result in forcible termination
of the process where shutdown hooks are not called. This is what
happens on Windows. The exit code in such a case is 1 which prevents
anything from waiting for the process to complete from detecting
that it ended as a result of a SIGINT, leaving it with no choice but
to report an error. This is what happens with mvn spring-boot:run
with a forked process on Windows and results in the build failing.

This commit updates RunProcess to allow the child process to handle
the SIGINT itself, waiting for up to five seconds for that to happen
before the process is then destroyed. Given this time, the child
process exits with 130 which RunMojo already handles correctly as
indicating that the process died due to SIGINT and the build completes
with success as a result.

Fixes gh-18936

* pr/18920:
  Polish "Remove reference to ConfigurationPropertiesScan in javadoc"
  Remove reference to ConfigurationPropertiesScan in javadoc

Closes gh-18920

See gh-18920

See gh-18920

See gh-18844

Closes gh-18844

Closes gh-18913

Previously, whitespace in between the keys and values in the JSON was
not trimmed correctly in BasicJsonParser which lead to it incorrectly
parsing JSON with whitespace between the opening of a list ([) and the
opening of a map ({).

This commit updates the parser to trim unwanted whitespace and adds a
test to AbstractJsonParserTests to verify the whitespace handling
behaviour across all JsonParser implementations.

Closes gh-18911

Closes gh-18912

Previously @ServletComponentScan did not work when there was a
component index on the classpath as it made an assumption about
the concrete type of the BeanDefinitions produced by scanning that
does not hold true when an index is present.

This commit updates the scanning and the handlers to correct the
assumpution by working with a bean definition type that is produced
by scanning both when there is and when there is not an index present.

To prevent the problem from reoccuring, a test that uses and index
has been added and the import of ScannedGenericBeanDefinition is now
prohibited by Checkstyle.

Closes gh-18910

Closes gh-18906

Fixes gh-18901

Closes gh-18903

Previously, as soon as the distribution of a release from Artifactory
to Bintray had been initiated we would start checking if it was
complete. This created a race condition between the distribution being
created and us checking if it was complete. If the check won the race
and happened before the creation, Bintray would respond with a 404.

This commit updates BintrayService to wait for up to 5 minutes for the
distribution to be created on Bintray. Once it has been created we
then wait for up to 40 minutes for it to be complete as we did before.

The use of Awaitility has been introduced in this commit to simplify
the logic required to wait for the distribution's creation and
completion.

Closes gh-18902

This commit makes sure that the health endpoint returns a default health
status when no contributors are available. Previously, it was returning
`null` which leads to a 404 when exposed via HTTP.

Closes gh-18676

Closes gh-18898

Closes gh-18897

Closes gh-18896

* pr/18855:
  Polish "Polish comment in pom.xml"
  Polish comment in pom.xml

Closes gh-18855

See gh-18855

See gh-18855

* pr/18883:
  Use try-with-resources blocks in JarFileArchiveTests

Closes gh-18883

See gh-18883

Prior to this commit constructor bound configuration properties could
not be mocked because it would fail validation from
ConfigurationPropertiesBeanDefinitionValidator. The MockitoPostProcessor
registers the mocked bean as a singleton and validation can be skipped if a
singleton for the type is found in the bean factory.

Fixes gh-18652

This commit fixes a few bugs related to constructor binding.
The ContructorFilter on the Bindable has been replaced with a
Binder level BinderConstructorProvider so that it can be used to
determine the constructor to use for nested properties as well.

Fixes gh-18810
Fixes gh-18670
Closes gh-18685
Closes gh-18894
Co-authored-by: Phillip Webb <pwebb@pivotal.io>

Closes gh-18892