多线程学习--异常,锁自动释放/同步不具继承性

浅浅的花香味﹌ 2023-10-27 07:07 92阅读 0赞

**`出现异常，锁自动释放：`**

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());
            }
        }
    }

public class ThreadA extends Thread {
        private Service service;
    
        public ThreadA(String name, Service service) {
            super(name);
            this.service = service;
        }
    
        @Override
        public void run() {
            service.testMethod();
        }
    }
    public class ThreadB extends Thread {
        private Service service;
    
        public ThreadB(String name, Service service) {
            super(name);
            this.service = service;
        }
    
        @Override
        public void run() {
            service.testMethod();
        }
    }

public class test{
        public static void main(String[] args) {
    
            try {
                Service service = new Service();
                ThreadA a = new ThreadA("a", service);
                a.start();
                Thread.sleep(500);
                ThreadB b = new ThreadB("b", service);
                b.start();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
    
        }
    }

结果：

ThreadName=a run beginTime=1544547881986
    ThreadName=a run exceptionTime=1544547885631
    Exception in thread "a" java.lang.NumberFormatException: For input string: "a"
    Thread b run Time=1544547885631
    	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    	at java.lang.Integer.parseInt(Integer.java:580)
    	at java.lang.Integer.parseInt(Integer.java:615)
    	at com.brianway.learning.java.multithread.synchronize.example6.Service.testMethod(Service.java:15)
    	at com.brianway.learning.java.multithread.synchronize.example6.ThreadA.run(ThreadA.java:16)

`同步不具继承性：子类重写父类带有synchronized的方法，无法将同步继承过来，如果子类该方法也需要实现同步，则在该方法上也需要加上synchronized标识该方法是同步方法。`