Where a realm is temporarily unavailable we have the RealmUnavailableException - in other cases however our API generally requires that null or empty representations are returned when identities can not be loaded or validation.

In a few cases RuntimeExceptions have crept into the implementations, we need to eliminate these as any code written according the API and not expecting them risks breaking for unexpected RuntimeExceptions.

Each method on the API should also be double checked to ensure it clearly documents what should happen if it can not return the desired result.