<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_USb9v8he-418945332/850/25/_/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="thomas11" id="email_thomas11" href="http://jira.qos.ch/secure/ViewProfile.jspa?name=thomas11" style="color:#326ca6;">Thomas Kappler</a>
     created <img src="http://jira.qos.ch/images/icons/issuetypes/improvement.png" height="16" width="16" border="0" align="absmiddle" alt="Improvement"> <a style='color:#326ca6;text-decoration:none;' href='http://jira.qos.ch/browse/LOGBACK-944'>LOGBACK-944</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-944'><strong>MDC.getCopyOfContextMap can return null, but MDC.setContextMap doesn't accept it</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/improvement.png" height="16" width="16" border="0" align="absmiddle" alt="Improvement">        Improvement
    </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%;">
                    1.0.13            </td>
</tr>
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    <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;">Created:</strong>
    </td>
    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
        03/Feb/14 11:22 AM
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</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;'>When using MDC and thread pools, code usually follows this pattern:</p>

<div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent">
<pre>final Map context = MDC.getCopyOfContextMap();
executor.submit(new Runnable() {
        @Override
        public void run() {
                MDC.setContextMap(context);
        }
</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>But if no MDC variables are set, getCopyOfContextMap() returns null and setContextMap then blows up. LogbackMDCAdapter.setContextMap uses Map.putAll which doesn't accept null. Therefore, one has to wrap the call to setContextMap in an annoying null check.</p>

<p style='margin-top:0;margin-bottom:10px;'>I suggest that setContextMap should handle a null argument gracefully by returning early. Alternatively, return Collections.emptyMap() or similar from getCopyOfContextMap.</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/minor.png" height="16" width="16" border="0" align="absmiddle" alt="Minor">                Minor
    </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="thomas11" id="email_thomas11" href="http://jira.qos.ch/secure/ViewProfile.jspa?name=thomas11" style="color:#326ca6;">Thomas Kappler</a>
                </td>
</tr>                                                                    </table>
                </td>
            </tr>
        </table>
    </td>
</tr>













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        </td><!-- End #email-page -->
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</table><!-- End #email-wrap -->
</div><!-- End #email-body -->