Java Stream API vs Collections

What are the main differences between Java Stream API and Collections?

The Java Stream API is designed for processing sequences of elements, while Collections are data structures that store elements. Streams allow for functional-style operations on collections, enabling more concise and readable code.

Can you give me an example of using Stream API?

Sure! For example, you can use the Stream API to filter a list of integers to find even numbers:

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
List<Integer> evenNumbers = numbers.stream()
                                    .filter(n -> n % 2 == 0)
                                    .collect(Collectors.toList());

When should I use Stream API instead of Collections?

Use Stream API when you need to perform complex data processing, such as filtering, mapping, or reducing data. Collections are better for simple data storage and retrieval.

Are there any performance differences between them?

Yes, Streams can be more efficient for large datasets as they can process elements in parallel. However, for small collections, the performance difference may be negligible.