Defer @Conditional processing on @Configuration classes until the bean
definitions are loaded, rather than when the @Configuration class is
parsed. This provides better support for @Conditional implementations
that inspect bean definitions.

This commit also fixes some minor problems with original implementation
and replaces the ConditionalAnnotationHelper class with
ConditionEvaluator.

Issue: SPR-10534

Update ConfigurationClassUtils to only consider beans with @Bean
methods as 'lite' configuration candidates.

Prior to this commit all @Component beans were considered 'lite'
configuration candidates which could result in a large number of
ConfigurationClass instance being created that would ultimately be
ignored.

Issue: SPR-10609

Update AnnotationBeanNameGenerator to only use the value attribute of
a @Component meta-annotated annotation when it is a String.

Issue: SPR-10580

Add support for the EnvironmentAware interface with ImportSelector
and ImportBeanDefinitionRegistrar implementations.

Issue: SPR-10602

Issue: SPR-10568

Issue: SPR-10546
(cherry picked from commit 6e4317eb)

Issue: SPR-10130

Refactor ConfigurationClassEnhancer so that BeanFactory instances are
not held against CGLIB Callback objects. Enhanced @Configuration classes
now use the BeanFactoryAware interface in order to obtain a BeanFactory.

This change has the additional benefit that a static final field can
now be used to hold all Callback instances.

Issue: SPR-10307

Add DeferredImportSelector interface that can be used to select imports
after all @Configuration beans have been processed.

Introduce new @Conditional annotation that can be used to filter
which @Configuration classes or methods are loaded. @Conditional
can be used directly or as a meta-annotation. Condition implementations
are provided via the 'Condition' interface and are free to filter based
on any criteria available at the time that they run. The
ConditionalContext provides access to the BeanDefinitionRegistry,
Environment and ConfigurableListableBeanFactory along with a
ResourceLoader and ClassLoader.

The existing @Profile annotation has been refactored as a @Conditional
with the added benefit that it can now be used as a method level
annotation.

Allow classes that are annotated with @Import to be considered as 'lite'
@Configuration candidates. Allows the AnnotationConfigApplicationContext
to directly register @Import beans even if they are not @Components.

Issue: SPR-10533

Exclude self @Component when parsing @ComponentScan annotations.

Issue: SPR-10531

Implementations of Spring's ImportSelector interface may
now implement any of the following *Aware interfaces and have their
respective methods called prior to #registerBeanDefinitions:

 - BeanFactoryAware
 - BeanClassLoaderAware
 - ResourceLoaderAware

Issue: SPR-10530

Add AnnotationConfigApplicationContext constructor allow use of a
custom DefaultListableBeanFactory.

Issue: SPR-10529

In particular, avoid accidental usage of ASM for core JDK types - which will fail in case of a new bytecode version in the JDK, even if the application itself has been compiled with an earlier bytecode target.

Issue: SPR-10292

Specifically, our CallbackFilter doesn't hold an implicit reference to the containing ConfigurationClassEnhancer class anymore.

Issue: SPR-10307

Issue: SPR-10261

Issue: SPR-10265

Minor formatting polish across that codebase. Primarily fixing
whitespace issues.

ConfigurationClassPostProcessor consistently uses ClassLoader, not loading core JDK annotations via ASM

Issue: SPR-10249

This reverts commit 45fa5082, reversing
changes made to a312d900.

Issue: SPR-10130

Issue: SPR-10128

  find . -type f -name "*.java" -or -name "*.aj" | \
    xargs perl -p -i -e "s/[ \t]*$//g" {} \;

Issue: SPR-10127

In particular, avoiding synchronized Sets and Maps wherever possible (preferring a ConcurrentHashMap even instead of a synchronized Set) and specifying appropriate ConcurrentHashMap initial capacities (even if we end up choosing 16).

Added "clearCache()" method to CachingMetadataReaderFactory, for clearing the metadata cache once not needed anymore - in particular when the MetadataReaderFactory instance is long-lived. Also added "setMetadataReaderFactory" method to ClassPathScanningCandidateComponentProvider, analogous to ConfigurationClassPostProcessor.

Issue: SPR-10058

Also, @Bean destroy method inference not applying for DisposableBean implementers anymore (avoiding double destruction).

Issue: SPR-10034

Issue: SPR-9589
Issue: SPR-9476