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POThread Deadlock
 

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    <p>I have 2 threads. One thread prints odd numbers and the second thread prints even numbers. Now, I have to execute the threads alternatively so that i can output 1,2,3,4,5,6,.....</p> <p>I have written a program for this and this is resulting in a deadlock. Can someone explain what is the problem with the code and how to rectify it?</p> <pre><code>class BooleanObject { boolean flag; BooleanObject(boolean flag) { this.flag = flag; } } class EvenThread extends Thread { Object lock; BooleanObject flagObj; EvenThread(Object o, BooleanObject flag) { lock = o; this.flagObj = flag; } public void run() { for (int i=2;i&lt;100;i+=2) { synchronized(lock) { if (flagObj.flag == false) { flagObj.flag = true; lock.notify(); } else { try { while (flagObj.flag == true) { lock.wait(); } } catch (InterruptedException e) { } } System.out.println(i); } } } } class OddThread extends Thread { Object lock; BooleanObject flagObj; OddThread(Object o, BooleanObject flag) { lock = o; this.flagObj = flag; } public void run() { for (int i=1;i&lt;100;i+=2) { synchronized(lock) { if (flagObj.flag == true) { flagObj.flag = false; lock.notify(); } else { try { while(flagObj.flag == false) { lock.wait(); } } catch (InterruptedException e) { } } System.out.println(i); } } } } public class EvenOddThreads { public static void main(String[] args) { Object obj = new Object(); BooleanObject flagObj = new BooleanObject(true); EvenThread et = new EvenThread(obj,flagObj); OddThread ot = new OddThread(obj,flagObj); et.setName("even thread"); ot.setName("odd thread"); et.start(); ot.start(); } } </code></pre>
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    1. COIs it homework?
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    2. COIts not homework. I am trying to understand multi-threading and the best way is to solve some problems (in my opinion)
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    3. COThe bug would be more obvious if you marked fields final.
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      1. USTom Hawtin - tackline
 

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