What is the Java Stream API and how does mapping work?

Can you explain what the Java Stream API is?

The Java Stream API is a powerful feature introduced in Java 8 that allows for functional-style operations on streams of elements, such as collections. It enables you to process data in a declarative way.

How does mapping work in the Stream API?

Mapping in the Stream API is done using the map method, which transforms each element in the stream into another form. For example, you can convert a list of strings to their lengths.

Can you give me a code example of using map?

Sure! Here's a simple example:

List<String> names = Arrays.asList("Alice", "Bob", "Charlie");
List<Integer> nameLengths = names.stream()
    .map(String::length)
    .collect(Collectors.toList());

This code converts a list of names into a list of their lengths.

What are some other operations I can perform with streams?

You can perform various operations like filtering with filter(), sorting with sorted(), and reducing with reduce(). Each of these methods allows you to manipulate the data in different ways.