import java.util.concurrent.ConcurrentHashMap;
public class ConcurrentHashMapExample {
public static void main(String[] args) {
ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
map.put("key1", 1);
map.put("key2", 2);
map.put("key3", 3);
int value = map.get("key1");
System.out.println("Value: " + value);
map.replace("key2", 4);
map.forEach((key, val) -> System.out.println(key + ": " + val));
map.remove("key3");
boolean containsKey = map.containsKey("key3");
System.out.println("Contains key 'key3': " + containsKey);
}
}
import java.util.concurrent.CopyOnWriteArrayList;
public class CopyOnWriteArrayListExample {
public static void main(String[] args) {
CopyOnWriteArrayList<Integer> list = new CopyOnWriteArrayList<>();
list.add(1);
list.add(2);
list.add(3);
int value = list.get(0);
System.out.println("Value: " + value);
list.set(1, 4);
for (Integer num : list) {
System.out.println("Value: " + num);
}
list.remove(2);
boolean contains = list.contains(2);
System.out.println("Contains value '2': " + contains);
}
}
