/*
This should always produce 0 as output since all three methods increment(), decrement(), value() are thread safe(synchronized). but it is returning 1
*/
class Counter implements Runnable {
private int c = 0;
public synchronized void increment() {
c++;
}
public synchronized void decrement() {
c--;
}
public synchronized int value() {
return c;
}
public void run() {
try {
this.increment();
Thread.sleep(1000);
this.decrement();
Thread.sleep(1000);
this.increment();
Thread.sleep(1000);
this.decrement();
Thread.sleep(1000);
}
catch (InterruptedException e){
return;
}
}
public static void main(String args[]) throws InterruptedException {
Counter c = new Counter();
new Thread(c).start();
new Thread(c).start();
System.out.println(c.value());
}
}
最佳答案
就像其他人所说的那样,您需要确保步骤已完成执行,为此您需要调用 join 。例如
public static void main(String args[]) throws InterruptedException {
Counter c = new Counter();
Thread t1 = new Thread(c).start();
Thread t2 = new Thread(c).start();
t1.join();
t2.join();
System.out.println(c.value());
}
应该可以正确运行
关于java - 在程序中得到不一致/错误的输出多线程java,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3631352/