What are the differences between Java 8 Stream API and Collections?

What are the main differences between Java 8 Stream API and Collections?

The Java 8 Stream API is designed for processing sequences of elements, while Collections are data structures. Streams allow for functional-style operations on collections, enabling more concise and readable code.

Can you give me an example of how to use 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);
List<Integer> evenNumbers = numbers.stream()
                                    .filter(n -> n % 2 == 0)
                                    .collect(Collectors.toList());

What are the performance implications of using Streams?

Streams can be more efficient for large data sets as they can leverage parallel processing. However, for small collections, the overhead of creating a stream may not be worth it.

When should I use Collections instead of Streams?

Use Collections when you need to store and manipulate data directly, especially for small datasets or when you need random access. Streams are better for bulk operations and transformations.