import java.util.ArrayList;import java.util.List;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;public class ReadWriteLockTest{    private static List<String> list = new ArrayList<String>();    public static void main(String[] args)    {        for(int i = 0; i < 10; i++)        {            list.add("init - " + i);        }        new Thread(new Runnable()        {            public void run()            {                try                {                    ReadWriteLockTest.add();                }                catch (Exception e)                {                    e.printStackTrace();                }            }        }).start();        new Thread(new Runnable()        {            public void run()            {                try                {                    ReadWriteLockTest.get();                }                catch (Exception e)                {                    e.printStackTrace();                }            }        }).start();    }        private static ReadWriteLock lock = new ReentrantReadWriteLock();    private static void add() throws Exception    {        for(int i = 0; i < 10; i++)        {            lock.writeLock().lock();            list.add("add-" + i);            lock.writeLock().unlock();            System.out.println("add " + i);            Thread.sleep(500);        }    }        private static void get() throws Exception    {        lock.readLock().lock();        for(String str : list)        {            System.out.println("get- " + str);            Thread.sleep(500);        }        lock.readLock().unlock();    }}