Compare
https://github.com/googleapis/java-firestore/blob/master/google-cloud-firestore/src/main/java/com/google/cloud/firestore/DocumentSnapshot.java#L336

with

https://github.com/googleapis/java-firestore/blob/master/google-cloud-firestore/src/main/java/com/google/cloud/firestore/DocumentSnapshot.java#L348

In the first example, if the field does not exist or is null, you return null. In the second case, you throw an NPE. This is confusing when the behavior is not consistent between different field types, and it is incorrect to label the methods that throw an NPE as Nullable, as they will never return null.