What's the difference between ContentObservable and DataSetObservable?

Question

They both inherit from Observable. And their functions do not differ by much, why not provide only a single class?

Answer 1

As you can see from code sources, DataSetObservable is sending notifications to a list of DataSetObserver objects, while ContentObservable is sending notifications to a list of ContentObserver objects

See sources: https://github.com/android/platform_frameworks_base/blob/master/core/java/android/database/DataSetObservable.java

https://github.com/android/platform_frameworks_base/blob/master/core/java/android/database/ContentObservable.java