// references/ImmutableInteger.java // (c)2017 MindView LLC: see Copyright.txt // We make no guarantees that this code is fit for any purpose. // Visit http://OnJava8.com for more book information. // The Integer class cannot be changed import java.util.*; import java.util.stream.*; public class ImmutableInteger { public static void main(String[] args) { List v = IntStream.range(0, 10) .mapToObj(Integer::new) .collect(Collectors.toList()); System.out.println(v); // But how do you change the int // inside the Integer? } } /* Output: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] */