Issue: SPR-16946

Provides a non-null guarantee for MethodMatcher's targetClass argument and strict separation between IntroductionAwareMethodMatcher and regular MethodMatcher, enabling DefaultAdvisorChainFactory to defer its IntroductionAdvisor determination until encountering an actual IntroductionAwareMethodMatcher (even behind union/intersection).

Issue: SPR-17068

This involves a new ResourceTransactionDefinition variant that JpaTransactionManager indicates a transaction-local EntityManager on. HibernateJpaDialect uses this indicator for hard read-only behavior.

Issue: SPR-16956

Issue: SPR-16987

Reorganize imports to ensure consistent ordering. This commit also
expands any `.*` static imports in favor of using fully-qualified
method references.

Issue: SPR-16968

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

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

Fix checkstyle violations for javadoc.

Issue: SPR-16968

(cherry picked from commit a2765c00)

Includes efficient canApply check for IntroductionAwareMethodMatcher.

Issue: SPR-16757

Issue: SPR-16733

Includes efficient check for same ClassLoader in ClassUtils.isVisible, efficient MethodMatchers check for IntroductionAwareMethodMatcher, and supertype method resolution in MethodMapTransactionAttributeSource.

Issue: SPR-16723

Issue: SPR-16717

Issue: SPR-16685

Issue: SPR-16675
Issue: SPR-16677

Issue: SPR-16488

Issue: SPR-16572

Includes consistent use of ClassUtils.toClassArray (as non-null variant)

Issue: SPR-16523

use assertNull instead of assertEquals(null, value),
declare delta as double value in assertEquals

Issue: SPR-16463

Issue: SPR-16225

Issue: SPR-16102

Issue: SPR-16092