多线程死锁问题（this锁和普通锁区别）

需求：写一个多线程死锁程序。思路：1、创建一个类Test 实现Runnable接口，并把任务封装到run()方法中。2、任务代码中用到两个同步代码块，并实现任务切换，来实现死锁。3，或者用同步函数和同步代码块，但能发现this锁的特殊。

第一种方法是，用两个同步代码块嵌套，来实现死锁。

package cm;

public class DeadLock {
public static void main(String []args){

Test t=new Test();
Thread s=new Thread(t,"one");
Thread s1=new Thread(t,"two");
s.start();
try {
Thread.sleep(10);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

t.flag=false;
s1.start();

}

}
class Test implements Runnable{
boolean flag=true;
Object obj =new Object();
Object obj1 =new Object();
public void run() {
if(flag)
{
while(true)
{	synchronized(obj){

System.out.println(Thread.currentThread()+"...lock obj.....");
try {
Thread.sleep(10);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
synchronized(obj1){
System.out.println(Thread.currentThread()+".....lock obj1.....");
}
}

}

}
else
while(true)
show();

}
private  void show() {
synchronized(obj1){
System.out.println(Thread.currentThread()+"obj1 lock....");
synchronized(obj){
System.out.println(Thread.currentThread()+"obj lock.....");

}
}
}

}

第二种死锁方式：

同步函数和同步代码块嵌套，可以发现的不同之处是。this锁由于是指向本类对象，故可以被同一个对象调用的同步函数同时持有

，而不排斥，普通锁只能被一个所持有，也就是说，s线程拿到了this锁同时，不影响s1线程拿到this锁。。package cm;public class DeadLock {public static void main(String []args){Test t=new Test();Thread s=new Thread(t,"one");Thread s1=new Thread(t,"two");s.start();try {Thread.sleep(10);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}t.flag=false;s1.start();}}class Test implements Runnable{boolean flag=true;Object obj =new Object();public void run() {if(flag){while(true){synchronized(obj){System.out.println(Thread.currentThread()+"...lock obj.....");try {Thread.sleep(10);}catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}show();}}}elsewhile(true)show();}private  void show() {System.out.println(Thread.currentThread()+"this lock....");synchronized(obj){System.out.println(Thread.currentThread()+"obj lock.....");}}}