锁的概念：

package com.bjsxt.height.lock020;

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

public class UseReentrantLock {
    
    private Lock lock = new ReentrantLock();
    
    public void method1(){
        try {
            lock.lock();
            System.out.println("当前线程:" + Thread.currentThread().getName() + "进入method1..");
            Thread.sleep(1000);
            System.out.println("当前线程:" + Thread.currentThread().getName() + "退出method1..");
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            
            lock.unlock();
        }
    }
    
    public void method2(){
        try {
            lock.lock();
            System.out.println("当前线程:" + Thread.currentThread().getName() + "进入method2..");
            Thread.sleep(2000);
            System.out.println("当前线程:" + Thread.currentThread().getName() + "退出method2..");
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            
            lock.unlock();
        }
    }
    
    public static void main(String[] args) {

        final UseReentrantLock ur = new UseReentrantLock();
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                ur.method1();
            }
        }, "t1");

        t1.start();
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                ur.method1();
            }
        }, "t2");

        t2.start();
        //System.out.println(ur.lock.getQueueLength());
    }   
}

package com.bjsxt.height.lock020;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class UseCondition {

    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();
    
    public void method1(){
        try {
            lock.lock();
            System.out.println("当前线程：" + Thread.currentThread().getName() + "进入等待状态..");
            Thread.sleep(3000);
            System.out.println("当前线程：" + Thread.currentThread().getName() + "释放锁..");
            condition.await();  // Object wait
            System.out.println("当前线程：" + Thread.currentThread().getName() +"继续执行...");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    
    public void method2(){
        try {
            lock.lock();
            System.out.println("当前线程：" + Thread.currentThread().getName() + "进入..");
            Thread.sleep(3000);
            System.out.println("当前线程：" + Thread.currentThread().getName() + "发出唤醒..");
            condition.signal();     //Object notify
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    
    public static void main(String[] args) {
        
        final UseCondition uc = new UseCondition();
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                uc.method1();
            }
        }, "t1");
        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                uc.method2();
            }
        }, "t2");
        t1.start();

        t2.start();
    }   
}