What are Java 8 Streams and Collectors?

Can you explain what Java 8 Streams and Collectors are?

Sure! Java 8 Streams are a new abstraction that allows you to process sequences of elements (like collections) in a functional style. Collectors are a part of the Streams API that help in accumulating the elements of a stream into a collection or summarizing them.

How do I use Collectors to group elements in a stream?

You can use the Collectors.groupingBy() method to group elements by a classifier function. For example, if you have a list of people, you can group them by their age.

Can you show me a code example of using Collectors?

Absolutely! Here's a simple example:

List<Person> people = Arrays.asList(new Person("Alice", 30), new Person("Bob", 25));
Map<Integer, List<Person>> groupedByAge = people.stream()
    .collect(Collectors.groupingBy(Person::getAge));

What are some other useful Collectors?

Some useful Collectors include Collectors.toList(), Collectors.toSet(), and Collectors.joining() for concatenating strings.