What is the difference between Observable, Completable and Single in RxJava

Question

Can anyone please explain the difference between Observable, Completable and Single in RxJava with clear examples?

In which scenario we use one over the others?

Answer 1

1. Flowable and Observable can represent finite or infinite streams. Flowable support back-pressure.
2. Single are streams with a single element.
3. Maybe are streams with either 0 or one element.
4. Finally a Completable represents a stream with no elements, i.e it can only complete without a value or fail.

A concise answer I found here on RXJava section.