Service registries are hierarchical. That is, a child registry may "hide" or "override" services from its parent registries. This allows for granular construction of registries as services become available.

1. BootstrapServiceRegistry is the base service registry, and may be constructed viaBootstrapServiceRegistryBuilder if customization is needed. For non-customized usage, these APIs may be bypassed completely.

2. The next level in a standard registry setup is theStandardServiceRegistry, which may be constructed usingStandardServiceRegistryBuilder if customization is needed. The builder optionally accepts sBootstrapServiceRegistry to use as a base. If none is provided, a default instance is produced, assuming sensible defaults in Java SE and EE environments, particularly with respect to classloading.