How can one transform a stream of objects into another data stream in RxJava?

In RxJava, the map operator is used to transform a stream of objects into another stream. It takes a function that converts each element of the source stream into a new element of a different type.

Example:

Observable<Integer> numbers = Observable.just(1, 2, 3);

Observable<String> strings = numbers.map(number -> "Number: " + number);

strings.subscribe(System.out::println);

The output in the console will be:

Number: 1
Number: 2
Number: 3

Besides map, there are other operators for transforming streams, such as flatMap for working with nested streams.