polishing
ReloadableResourceBundleMessageSource uses ConcurrentHashMaps and ReentrantLocks instead of synchronization

Issue: SPR-10500
AbstractAutowireCapableBeanFactory avoids synchronization in filterPropertyDescriptorsForDependencyCheck

Issue: SPR-12106
Polishing
ServerEndpointExporter can initialize itself based on a late-provided ServletContext as well (for Boot)

Also allows for direct setting of a ServerContainer and for custom triggering of endpoint registration.

Issue: SPR-12109
Polishing
@PropertySource gets parsed as early as possible

Other PropertySources and in particular @ComponentScan can benefit from previously declared property sources on the same configuration class.

Issue: SPR-12110
Issue: SPR-12111
PropertySource implementations perform conversion to String arrays via StringUtils (getting rid of EMPTY_NAMES_ARRAY)
Merge pull request #3 from spring-projects/master

Merge pull request from spring-projects/master