// references/CloneArrayList.java // (c)2021 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 clone() operation works for only a few // items in the standard Java library import java.util.*; import java.util.stream.*; class Int { private int i; Int(int ii) { i = ii; } public void increment() { i++; } @Override public String toString() { return Integer.toString(i); } } public class CloneArrayList { public static void main(String[] args) { ArrayList v = IntStream.range(0, 10) .mapToObj(Int::new) .collect(Collectors .toCollection(ArrayList::new)); System.out.println("v: " + v); @SuppressWarnings("unchecked") ArrayList v2 = (ArrayList)v.clone(); // Increment all v2's elements: v2.forEach(Int::increment); // See if it changed v's elements: System.out.println("v: " + v); } } /* Output: v: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] v: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] */