两个线程的同步ArrayList -写入和读取

import java.util.ArrayList;

public class SyncArrayListExample {
    private ArrayList<Integer> list = new ArrayList<>();

    public synchronized void addElement(int element) {
        list.add(element);
    }

    public synchronized int getElement(int index) {
        return list.get(index);
    }
}

import java.util.ArrayList;
import java.util.concurrent.locks.ReentrantLock;

public class SyncArrayListExample {
    private ArrayList<Integer> list = new ArrayList<>();
    private ReentrantLock lock = new ReentrantLock();

    public void addElement(int element) {
        lock.lock();
        try {
            list.add(element);
        } finally {
            lock.unlock();
        }
    }

    public int getElement(int index) {
        lock.lock();
        try {
            return list.get(index);
        } finally {
            lock.unlock();
        }
    }
}

import java.util.concurrent.CopyOnWriteArrayList;

public class SyncArrayListExample {
    private CopyOnWriteArrayList<Integer> list = new CopyOnWriteArrayList<>();

    public void addElement(int element) {
        list.add(element);
    }

    public int getElement(int index) {
        return list.get(index);
    }
}