当一个线程值执行的代码出现异常时，其所持有的锁会自动释放
/**
* @author wuyoushan
* @date 2017/4/10.
*/
public class Service {
synchronized public void testMethod(){
if(Thread.currentThread().getName().equals("a")){
System.out.println("ThreadName="+Thread.currentThread().getName()+
" run beginTime="+System.currentTimeMillis());
int i=1;
while(i==1){
if((""+Math.random()).substring(0,8).equals("0.123456")){
System.out.println("ThreadName="
+Thread.currentThread().getName()
+" run exceptionTime="
+System.currentTimeMillis());
Integer.parseInt("a");
}
}
}else{
System.out.println("Thread B run Time="+System.currentTimeMillis());
}
}
}
/**
* @author wuyoushan
* @date 2017/4/4.
*/
public class ThreadA extends Thread{
private Service service;
public ThreadA(Service service){
super();
this.service=service;
}
@Override
public void run() {
super.run();
service.testMethod();
}
}
/**
* @author wuyoushan
* @date 2017/4/4.
*/
public class ThreadB extends Thread{
private Service service;
public ThreadB(Service service){
super();
this.service=service;
}
@Override
public void run() {
super.run();
service.testMethod();
}
}
/**
* @author wuyoushan
* @date 2017/3/14.
*/
public class Test {
public static void main(String[] args) {
try{
Service service=new Service();
ThreadA a=new ThreadA(service);
a.setName("a");
a.start();
a.sleep(200);
Thread.sleep(500);
ThreadB b=new ThreadB(service);
b.setName("b");
b.start();
}catch (InterruptedException e){
e.printStackTrace();
}
}
}
程序的运行结果为:
ThreadName=a run beginTime=1491870317217
ThreadName=a run exceptionTime=1491870317336
Exception in thread "a" java.lang.NumberFormatException: For input string: "a"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:492)
at java.lang.Integer.parseInt(Integer.java:527)
at wys.test.Service.testMethod(Service.java:20)
at wys.test.ThreadA.run(ThreadA.java:19)
Thread B run Time=1491870317918
线程a出现异常并释放锁，线程b进入方法正常打印，实验的结论就是出现异常的锁被自动释放了。
摘选自 java多线程核心编程技术-2.1.7
