org.springframework.core.env
Interfaces 
ConfigurableEnvironment
ConfigurablePropertyResolver
Environment
EnvironmentCapable
PropertyResolver
PropertySources
Classes 
AbstractEnvironment
AbstractPropertyResolver
CommandLinePropertySource
EnumerablePropertySource
JOptCommandLinePropertySource
MapPropertySource
MutablePropertySources
PropertiesPropertySource
PropertySource
PropertySource.StubPropertySource
PropertySourcesPropertyResolver
SimpleCommandLinePropertySource
StandardEnvironment
SystemEnvironmentPropertySource
Exceptions 
MissingRequiredPropertiesException