Java CopyOnWriteArrayList example 2018-04-04 03:39
It will throw ConcurrentModificationException when multiple threads modify ArrayList. If the elements are not too much, CopyOnWriteArrayList is a good choice. CopyOnWriteArrayList copies elements when add new element. It is not recommend to using it when the elements are too many. (It is expensive to copy too many elements.)
ArrayList throw ConcurrentModificationException
public class ConcurrentModificationArrayListClient {
public static void main(String[] args) throws InterruptedException {
List<String> list = new ArrayList<>();
Thread subThread = new Thread(new Runnable() {
int index = 0;
@Override
public void run() {
while (true) {
list.add("index" + index);
index++;
}
}
});
subThread.start();
Thread.sleep(1000);
while (true) {
System.out.println(list.toString());
}
}
}
CopyOnWriteArray
public class CopyOnWriteArrayListClient {
public static void main(String[] args) throws InterruptedException {
List<String> list = new CopyOnWriteArrayList<>();
Thread subThread = new Thread(new Runnable() {
int index = 0;
@Override
public void run() {
while (true) {
list.add("index" + index);
index++;
}
}
});
subThread.start();
Thread.sleep(1000);
while (true) {
System.out.println(list.toString());
}
}
}
EOF