<style>
/* Changing the layout to use less space for mobiles */
@media screen and (max-device-width: 480px), screen and (-webkit-min-device-pixel-ratio: 2) {
    #email-body { min-width: 30em !important; }
    #email-page { padding: 8px !important; }
    #email-banner { padding: 8px 8px 0 8px !important; }
    #email-avatar { margin: 1px 8px 8px 0 !important; padding: 0 !important; }
    #email-fields { padding: 0 8px 8px 8px !important; }
    #email-gutter { width: 0 !important; }
}
</style>
<div id="email-body">
<table id="email-wrap" align="center" border="0" cellpadding="0" cellspacing="0" style="background-color:#f0f0f0;color:#000000;width:100%;">
    <tr valign="top">
        <td id="email-page" style="padding:16px !important;">
            <table align="center" border="0" cellpadding="0" cellspacing="0" style="background-color:#ffffff;border:1px solid #bbbbbb;color:#000000;width:100%;">
                <tr valign="top">
                    <td bgcolor="#003366" style="background-color:#003366;color:#ffffff;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;line-height:1;"><img src="http://jira.qos.ch/s/en_USb9v8hf-418945332/850/27/_/jira-logo-scaled.png" alt="" style="vertical-align:top;" /></td>
                </tr><tr valign="top">
    <td id="email-banner" style="padding:32px 32px 0 32px;">
        
                
        
        
            <table align="left" border="0" cellpadding="0" cellspacing="0" width="100%" style="width:100%;">
    <tr valign="top">
        <td style="color:#505050;font-family:Arial,FreeSans,Helvetica,sans-serif;padding:0;">
                                        <img id="email-avatar" src="http://jira.qos.ch/secure/useravatar?avatarId=10122" alt="" height="48" width="48" border="0" align="left" style="padding:0;margin: 0 16px 16px 0;" />
                        <div id="email-action" style="padding: 0 0 8px 0;font-size:12px;line-height:18px;">
                                    <a class="user-hover" rel="alex.rufous" id="email_alex.rufous" href="http://jira.qos.ch/secure/ViewProfile.jspa?name=alex.rufous" style="color:#326ca6;">Alex</a>
     created <img src="http://jira.qos.ch/images/icons/issuetypes/bug.png" height="16" width="16" border="0" align="absmiddle" alt="Bug"> <a style='color:#326ca6;text-decoration:none;' href='http://jira.qos.ch/browse/LOGBACK-1087'>LOGBACK-1087</a>
            </div>
                        <div id="email-summary" style="font-size:16px;line-height:20px;padding:2px 0 16px 0;">
                <a style='color:#326ca6;text-decoration:none;' href='http://jira.qos.ch/browse/LOGBACK-1087'><strong>ConcurrentModificationException is thrown from BasicStatusManager.fireStatusAddEvent on iteration through status listeners whilst StatusListener is removed in a separate thread</strong></a>
            </div>
                    </td>
    </tr>
</table>
    </td>
</tr>
<tr valign="top">
    <td id="email-fields" style="padding:0 32px 32px 32px;">
        <table border="0" cellpadding="0" cellspacing="0" style="padding:0;text-align:left;width:100%;" width="100%">
            <tr valign="top">
                <td id="email-gutter" style="width:64px;white-space:nowrap;"></td>
                <td>
                    <table border="0" cellpadding="0" cellspacing="0" width="100%">
                        <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Issue Type:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                <img src="http://jira.qos.ch/images/icons/issuetypes/bug.png" height="16" width="16" border="0" align="absmiddle" alt="Bug">        Bug
    </td>
</tr>                        <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Affects Versions:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                    1.1.3,                     1.1.2            </td>
</tr>
                        <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Assignee:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                                        <a class="user-hover" rel="logback-dev@qos.ch" id="email_logback-dev@qos.ch" href="http://jira.qos.ch/secure/ViewProfile.jspa?name=logback-dev%40qos.ch" style="color:#326ca6;">Logback dev list</a>
                </td>
</tr>                                                <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Components:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                    logback-classic            </td>
</tr>
                        <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Created:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
        09/Jul/15 11:54 AM
    </td>
</tr>                        <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Description:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
        <p style='margin-top:0;margin-bottom:10px;'>ConcurrentModificationException can be thrown whilst status event is fired out into registered StatusListeners but one of the listener is removed at the same time from a different thread.</p>

<p style='margin-top:0;margin-bottom:10px;'>An example of stack trace for the issue is provided below</p>
<div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent">
<pre>11:31:11,081 |-ERROR in ch.qos.logback.core.rolling.RollingFileAppender[logfile] - Appender [logfile] failed to append. java.util.ConcurrentModificationException
    at java.util.ConcurrentModificationException
    at     at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
    at     at java.util.ArrayList$Itr.next(ArrayList.java:831)
    at     at ch.qos.logback.core.BasicStatusManager.fireStatusAddEvent(BasicStatusManager.java:86)
    at     at ch.qos.logback.core.BasicStatusManager.add(BasicStatusManager.java:59)
    at     at ch.qos.logback.core.recovery.ResilientOutputStreamBase.addStatus(ResilientOutputStreamBase.java:157)
    at     at ch.qos.logback.core.recovery.ResilientOutputStreamBase.addStatusIfCountNotOverLimit(ResilientOutputStreamBase.java:138)
    at     at ch.qos.logback.core.recovery.ResilientOutputStreamBase.postIOFailure(ResilientOutputStreamBase.java:101)
    at     at ch.qos.logback.core.recovery.ResilientOutputStreamBase.flush(ResilientOutputStreamBase.java:82)
    at     at ch.qos.logback.core.encoder.LayoutWrappingEncoder.doEncode(LayoutWrappingEncoder.java:137)
    at     at ch.qos.logback.core.OutputStreamAppender.writeOut(OutputStreamAppender.java:194)
    at     at ch.qos.logback.core.FileAppender.writeOut(FileAppender.java:209)
    at     at ch.qos.logback.core.OutputStreamAppender.subAppend(OutputStreamAppender.java:219)
    at     at ch.qos.logback.core.rolling.RollingFileAppender.subAppend(RollingFileAppender.java:182)
    at     at ch.qos.logback.core.OutputStreamAppender.append(OutputStreamAppender.java:103)
    at     at ch.qos.logback.core.UnsynchronizedAppenderBase.doAppend(UnsynchronizedAppenderBase.java:88)
    at     at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:48)
    at     at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:273)
    at     at ch.qos.logback.classic.Logger.callAppenders(Logger.java:260)
    at     at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:442)
    at     at ch.qos.logback.classic.Logger.filterAndLog_0_Or3Plus(Logger.java:396)
    at     at ch.qos.logback.classic.Logger.error(Logger.java:559)
</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>The easiest way to reproduce it would be to implement status listener unregistering itself from addStatusEvent:</p>

<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java">
class MyListener <span class="code-keyword">implements</span> StatusListener
{
  <span class="code-keyword">private</span> StatusManager _statusManager;
  <span class="code-keyword">public</span> MyListener(StatusManager statusManager)
  {
    _statusManager = statusManager;
  }

  @Override
  <span class="code-keyword">public</span> void addStatusEvent(Status status)
  {
    _statusManager.remove(<span class="code-keyword">this</span>);
  }
}

</pre>
</div></div> 

<p style='margin-top:0;margin-bottom:10px;'>The issue affects the application creating and removing Appenders dynamically and registering/unregistering StatusListeners on appender creation and removing accordingly.</p>
    </td>
</tr>
                                                                                                <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Project:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
        <a style="color:#326ca6;" href="http://jira.qos.ch/browse/LOGBACK">logback</a>
    </td>
</tr>                                                <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Priority:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                        <img src="http://jira.qos.ch/images/icons/priorities/major.png" height="16" width="16" border="0" align="absmiddle" alt="Major">                Major
    </td>
</tr>
                        <tr valign="top">
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
        <strong style="font-weight:normal;color:#505050;">Reporter:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                                        <a class="user-hover" rel="alex.rufous" id="email_alex.rufous" href="http://jira.qos.ch/secure/ViewProfile.jspa?name=alex.rufous" style="color:#326ca6;">Alex</a>
                </td>
</tr>                                                                    </table>
                </td>
            </tr>
        </table>
    </td>
</tr>













            </table>
        </td><!-- End #email-page -->
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        <td style="color:#505050;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:10px;line-height:14px;padding: 0 16px 16px 16px;text-align:center;">
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</table><!-- End #email-wrap -->
</div><!-- End #email-body -->