This commit fixes an issue where DataBufferUtils.join() would not
release databuffers that preceded an error signal.

Issue: SPR-17025

Issue: SPR-17240

Issue: SPR-17215

Issue: SPR-17198

Includes XMLUnit 2.6.1 and Undertow 2.0.13.

Issue: SPR-16115

Issue: SPR-17191

Includes caching of declared annotation arrays and combined searching for several annotation types (used in SpringCacheAnnotationParser).

Issue: SPR-16933

Issue: SPR-17174

javax.xml.stream.Location is already there as an import there is no need
to use the FQCN in the handleDtd method.

Issue: SPR-17169

Issue: SPR-17154

Issue: SPR-16946

This commit provides a data type to represents a size in bytes and other
standard unit.

Issue: SPR-17154

Includes Java 8 getDeclaredAnnotation shortcut for lookup on Class.

Issue: SPR-17146

The dependency to Apache Commons has been removed in https://github.com/spring-projects/spring-framework/commit/51252ebbcaa9e65aee83311aec25ca3c7c6d7d37#diff-95dc9d8756aa91afb2ac28454f1b634c, but the javadoc still mentions it.

Issue: SPR-17143

Issue: SPR-17136

Issue: SPR-16933

Issue: SPR-16398

Includes pre-sizing of LinkedHashSet for conversion from array.

Issue: SPR-17123
Issue: SPR-17074

Issue: SPR-17188

Includes consistent (non-)use of AnnotationUtils/AnnotatedElementUtils.

Issue: SPR-16933

This revision considers any java/javax and org.springframework.lang annotations as not synthesizable upfront, checking not only in isSynthesizable but also at synthesizeAnnotation(Array) level.

Issue: SPR-16933

Empty Maps are preferably initialized without capacity (not initializing them at all or lazily initializing with default capacity when needed).

Issue: SPR-17105