Can you explain what the map method is in the context of Java's Stream API?

The map method in Java's Stream API is used to transform elements of a stream from one type to another. It takes a function that is applied to each element of the stream and returns a new stream with the results of that function.

For example, if you have a stream of strings and want to get a stream of their lengths, you can use map:

List<String> words = Arrays.asList("apple", "banana", "cherry");
List<Integer> lengths = words.stream()
    .map(String::length)
    .collect(Collectors.toList());

System.out.println(lengths); // Outputs [5, 6, 6]

Thus, map allows for easy and convenient transformation of data in a stream without modifying the original stream.