Issue: SPR-16968

Issue: SPR-16978

Allows for skipping the now-deprecated postProcessPropertyValues callback with its expensive PropertyDescriptor retrieval requirement. RequiredAnnotationBeanPostProcessor (which is dependent on postProcessPropertyValues) and the @Required annotation itself are also deprecated now: in favor of constructor injection (or afterPropertiesSet).

Issue: SPR-16918

Update code that has accidentally used spaces instead of tabs.
Also remove all trailing whitespace.

Issue: SPR-16968

Update classes that override `equals()` to ensure that they also
implement `hashCode()`.

Issue: SPR-16968

Ensure that `this.` is never used when accessing loggers.

Issue: SPR-16968

Ensure that `this.` is used consistently when accessing class
fields.

Issue: SPR-16968

Update all classes so that inner classes are always last. Also
ensure that utility classes are always final and have a private
constructor and make exceptions final whenever possible.

Issue: SPR-16968

Update all code to use a consistent block style.

Issue: SPR-16968

Update all annotations so that each is on its own line and
consistently use the short form (i.e. don't use `value=`) when
possible.

Issue: SPR-16968

Fix checkstyle violations for javadoc.

Issue: SPR-16968

Issue: SPR-12458

(cherry picked from commit a2765c00)

Issue: SPR-16849

Issue: SPR-16871

Includes nullable return value for getClassLoader() with corresponding notes in applicable javadoc.

Issue: SPR-16866

Includes removal of StrictMapAppenderConstructor for compatibility with SnakeYAML 1.21.

Issue: SPR-16791

Issue: SPR-16783

Prior to this commit, a YAML entry that define an empty array value was
lost. This commit makes sure to flag it with an empty String, which
corresponds as an empty comma separated list of entries in the
properties format.

Issue: SPR-16769

See gh-1803

Issue: SPR-16720

Note: Some symbol combinations (including <=) serve as textual symbol
replacements in AsciiDoc.

http://asciidoctor.org/docs/asciidoc-syntax-quick-reference/#text-replacement

Issue: SPR-15756

Issue: SPR-16646

Issue: SPR-16625

Issue: SPR-16620

Issue: SPR-16625
Issue: SPR-16627

Issue: SPR-16628

Use Collection.removeIf() where possible

Issue: SPR-16622

Issue: SPR-16581

Issue: SPR-16568