AbstractServiceRegistryImpl.java

	@Override
	public synchronized void deRegisterChild(ServiceRegistryImplementor child) {
		if ( childRegistries == null ) {
			throw new IllegalStateException( "No child ServiceRegistry registrations found" );
		}
		childRegistries.remove( child );
		
		if ( childRegistries.isEmpty() ) {
		  if ( !TransientServiceRegistry.class.isInstance( child ) ) {
  		  autoClose();
		  }
		}
	}
	
	protected void autoClose() {
	  if ( autoCloseRegistry ) {
		  log.debug(
					"Implicitly destroying ServiceRegistry on de-registration " +
							"of all child ServiceRegistries"
			);
			destroy();
		}
		else {
			log.debug(
					"Skipping implicitly destroying ServiceRegistry on de-registration " +
							"of all child ServiceRegistries"
			);
		}
  }

MetadataServiceRegistryImpl.java

class MetadataServiceRegistryImpl extends AbstractServiceRegistryImpl, TransientServiceRegistry {
  ...
}

TransientServiceRegistry.java

/**
 * Marker interface for ServiceRegistry impls that
 * should be excluded from consideration for their
 * parent registry's "auto-close" checks.
 */
public interface TransientServiceRegistry {
}