Snake YAML allows for duplicate keys in map nodes. See
https://code.google.com/p/snakeyaml/issues/detail?id=199

This commit uses a dedicated Constructor extension that explicitly
checks for such duplicate keys.

Issue: SPR-12318

Issue: SPR-12250

Issue: SPR-12232

Issue: SPR-12241

Introduced addScope convenience method on CustomScopeConfigurer (for use in WebSocket configuration)

Issue: SPR-12248

Issue: SPR-12241

Issue: SPR-12235

Issue: SPR-12187
(cherry picked from commit 29abca53)

Issue: SPR-12187

Issue: SPR-12167

Issue: SPR-12161

Issue: SPR-12185

Issue: SPR-12185

Issue: SPR-12185

Issue: SPR-11310
Issue: SPR-10548

AbstractAutowireCapableBeanFactory avoids early FactoryBean instantiation on currently created configuration bean

Issue: SPR-12141

ExtendedBeanInfo uses explicit hashCode calculation (as defensive measure against JDK PropertyDescriptor changes)

Issue: SPR-10508
Issue: SPR-8080

AbstractAutowireCapableBeanFactory calls postProcessBeforeInstantiation with fully resolved target type

Issue: SPR-12140
Issue: SPR-12142

AbstractAutowireCapableBeanFactory avoids synchronization in filterPropertyDescriptorsForDependencyCheck

Issue: SPR-12106

Issue: SPR-10614

DefaultSingletonBeanRegistry performs non-synchronized checks for existing entries in dependentBeanMap and containedBeanMap

Also adding alias resolution to isDependent's algorithm (for circular dependency detection).

Issue: SPR-8834
Issue: SPR-7966

Issue: SPR-10542

Issue: SPR-12102

Issue: SPR-12102

Lookup methods can support arguments, find a target bean based on the return type, and be identified by an @Lookup annotation

Issue: SPR-7431
Issue: SPR-5192

Issue: SPR-11235

Issue: SPR-12018

Issue: SPR-12018

This commit fixes a potential NPE when determining the priority of a
bean instance in case multiple candidates exist and no bean was marked
as @Primary

Issue: SPR-12024