使用jprofile研究线程分配和同步以发现死锁和数据竞争问题，提高性能

死锁示例程序：ThreadTest，这是经典的同步嵌套发生死锁的示例；

public class ThreadTest {    public static Object lock1 = new Object();    public static Object lock2 = new Object();    public static void method1() {        trace("Inside method1");        synchronized (lock1) {            trace("Method1 got lock1");            doSomething();            synchronized (lock2) {                trace("Method1 got lock2, sleeping");                doSomething();                trace("Method1 returning");            }        }    }    public static void method2() {        trace("Inside method2");        synchronized (lock2) {            trace("Method2 got lock2");            doSomething();            synchronized (lock1) {                trace("Method2 got lock1, sleeping");                doSomething();                trace("Method2 returning");            }        }    }    public static void doSomething() {        try {            Thread.sleep(5*1000);        }        catch (InterruptedException x) {            x.printStackTrace();        }        trace("Waiking up");    }    public static void trace(String msg) {        System.out.println(Thread.currentThread() + " : " + msg);    }    public static void main(String[] args) throws Exception {        new Thread(new Runnable() {            public void run() {                method1();            }        }).start();        new Thread(new Runnable() {            public void run() {                method2();            }        }).start();    }}

运行：

可以看到两个线程一直阻塞；

查看当前锁视图：

右键导出：

可以看到线程阻塞情况的文字描述；

死锁的解锁秘籍是获取锁的顺序保持一致；