A class that can statically hold a Spring application context for later easy retrieval. It is recommended that you store the context in this holder once the
context is created in a WebApplicationInitializer. It can then be easily retrieved from a JavaConfig @Bean annotated static method that returns a Bean
Factory Post Processor (BFPP) such as a property source place holder configurer.
Note that this class should only be used when there is no easy way to get a hold of the context using normal means such as autowiring and making a class
ApplicationContextAware.