whats wrong

Question about the task

Arrange wait and notify methods

Java Multithreading, Level 7, Lesson 9

Under discussion

Output is same in intellij idea

package com.codegym.task.task27.task2710; /* Arrange wait and notify methods */ public class Solution { public static void main(String[] args) { Mail mail = new Mail(); Thread server = new Thread(new MailServer(mail)); Thread amigo = new Thread(new Person(mail)); server.start(); amigo.start(); } }

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MaGaby2280

Level 41 , Guatemala City, Guatemala

8 December 2020, 19:16

The problem that I see, is that the synchronized blocks should be inside the try blocks, in all classes, so that they work in a multithreaded environment.

Wei Cui

Level 39 , Newark, United States

2 April 2020, 22:34

//person
  @Override
    public void run() {
        String name = Thread.currentThread().getName();
        try {
            Thread.sleep(1000);
            // do something here
            synchronized (mail) {
                mail.setText("Person [" + name + "] wrote an email 'AAA'");
                mail.notifyAll();
            }

            // do something here
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

Wei Cui

Level 39 , Newark, United States

2 April 2020, 22:33

//mailServer
public void run() {
    long startTime = System.currentTimeMillis();
    // do something here
    synchronized (mail) {
        while (mail.getText() == null) {
            try {
                mail.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

Seb

Level 41 , Crefeld, Germany

30 January 2020, 14:58

I believe there are two main issues here. First and foremost take another look at the method signatures in your Mail class. How about adding synchronized? ;-) You can then try to validate, but it may still not work. In your MailServer class only surround the part after long startTime = System.currentTimeMillis(); with the synchronized (mail) lock. And I would add a String variable that you set equal to the value received by mail.getText(). Then use this variable in the format statement instead of the call to mail.getText(). Why? Well, because otherwise you won't compute and output the correct duration of receiving the mail. (Remember there's a call to sleep(1000) in the Person class...) The program may validate now. If not, then also adjust your Person class. Wrap the synchronized (mail) lock only around the mail.setText method. That's it. :-)