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POIs it a good way to prevent ConcurrentModificationException
 

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    <p>The another question is about <strong>synchronized</strong>. I have also a run() in class Note,because i want to output each element in notes every 5 minutes. But i get always exception:java.util.ConcurrentModificationException,if i try to make more meetings in main. so i applay synchronized to the list notes which may be added a new meeting when i iterate over notes.My run method like this:</p> <p><strong>Is it correct way hier on list notes to synchronized to prevent ConcurrentModificationException ?</strong>(In my program it works.I get never this exception now)</p> <p>A Meeting class and Note class may likes this:</p> <pre><code>public class Meeting{ public Meeting(Note note_1,Note note_2){ note_1.addElement(this); note_2.addElement(this);} //another method hier } public class Note implements Runnable{ public final List&lt;Meeting&gt; notes = new ArrayList&lt;Meeting&gt;(); public void addElement(Meeting n){ entries.add(n); } @Override public void run(){ while(true) { for(Meeting n : notes){ System.out.println(n.toString);} } try{ Thread.sleep(10);} } } } </code></pre> <p>I get always exception error about <strong>exception:java.util.ConcurrentModificationException</strong> if i try to make more Meeting in main ,So i changes a littel in class Note,likes this :</p> <pre><code> private static final List&lt;Entry&gt; entries = Collections.synchronizedList(new ArrayList&lt;Entry&gt;()); </code></pre> <p>and in run()</p> <pre><code>@Override public void run() { while(true){ synchronized(notes){ for(Entry n : entries){ //do something } } try { Thread.sleep(10); } catch (InterruptedException e ) { } } } </code></pre> <p>}</p>
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    1. COWhile the exception was what brought you here, I should also point out that your logic is not ideal, since [you shouldn't publish a reference to `this` during construction](http://www.ibm.com/developerworks/java/library/j-jtp0618.html) if you want to use multiple threads, as it can break invariants that must "always" hold. Also, indenting your code properly and consistently will help readability a surprising amount.
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      1. USAndrzej Doyle
    2. COThanks Andrzej and Sorry that my code is not properly posted.Multiplethreads doesnt lead to ConcurrentModificationException in my program. It occurs when i iterate over the list in class Note and maybe a new meeting-object wants to add itself to the list
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