Нічого не робив окрім
new CopyOnWriteArrayList<String>(), але пише не змінювати метод copyOnWriteSolution, який я взагалі не чіпавpackage ua.javarush.task.task28.task2804;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ThreadLocalRandom;
/*
Magic class
*/
public class Solution {
public static void main(String[] args) throws InterruptedException {
Solution solution = new Solution();
List<String> list = new CopyOnWriteArrayList<String>();/* create object of this magic class here*/;
solution.startUpdatingThread(list);
solution.copyOnWriteSolution(list);
solution.stopUpdatingThread();
/* Example output
size = 0
Element: s781859336
Element: s1453499757
Element: s911312405
Element: s-877520242
Element: s-1636258097
size = 5
Element2: s781859336
Element2: s1453499757
Element2: s911312405
Element2: s-877520242
Element2: s-1636258097
Element2: s-1739827856
Element2: s-938954654
Element2: s925086217
size = 8
*/
}
public void copyOnWriteSolution(List<String> list) throws InterruptedException {
System.out.println("size = " + list.size());
System.out.println();
Thread.sleep(20);
for (String element : list) { //создает новую копию на момент создания итератора
System.out.println("Element: " + element);
}
System.out.println("size = " + list.size());
System.out.println();
Thread.sleep(20);
for (String element : list) { //создает новую копию на момент создания итератора
System.out.println("Element2: " + element);
}
System.out.println("size = " + list.size());
stopUpdatingThread();
}
public void stopUpdatingThread() throws InterruptedException {
t.stop();
t.join();
}
private Thread t;
private void startUpdatingThread(final List<String> list) {
t = new Thread(new Runnable() {
@Override
public void run() {
for (int i = 0; i < 20; i++) {
list.add("s" + ThreadLocalRandom.current().nextInt());
try {
Thread.sleep(5);
} catch (InterruptedException e) {
}
}
}
});
t.start();
}
}