title: Logback AsyncAppender unable to print method name and line number
body: <p>I am using logback AsyncAppender ch.qos.logback.core.rolling.RollingFileAppender to print logs to file with following configuration. Everything is working fine if printing on console but in log file method name and line number are printing as "?" character. </p>
  
  <p><strong>Logback Configuration</strong></p>
  
  <pre><code>&lt;appender name="activity_appender"
          class="ch.qos.logback.core.rolling.RollingFileAppender"&gt;
          &lt;File&gt;${log.folder}/${log.activity.fileName}&lt;/File&gt;
          &lt;encoder&gt;
              &lt;pattern&gt;%d{YYYY-MM-dd HH:mm:ss.SSS} -APP- %X{HOST} %X{requestId} [%t] %.-5level %logger{60}.%M-%L - %msg %n&lt;/pattern&gt;
          &lt;/encoder&gt;
          &lt;rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy"&gt;
              &lt;!-- rollover daily --&gt;
              &lt;fileNamePattern&gt;${log.folder}/${log.activity.fileName}-%d{YYYY-MM-dd}.%i
              &lt;/fileNamePattern&gt;
              &lt;timeBasedFileNamingAndTriggeringPolicy
                  class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"&gt;
                  &lt;!-- or whenever the file size reaches 100MB --&gt;
                  &lt;maxFileSize&gt;${log.file.maxsize}&lt;/maxFileSize&gt;
              &lt;/timeBasedFileNamingAndTriggeringPolicy&gt;
          &lt;/rollingPolicy&gt;
      &lt;/appender&gt;
  </code></pre>
  
  <p>Sample Output</p>
  
  <pre><code>2015-08-11 16:30:00.051 -APP-   [scheduler-1] WARN c.some.package.class.?-? - Configuration not present for configType:global or keysms.template Picking default value: 2 
  </code></pre>
  
  <p>Required Output</p>
  
  <pre><code>2015-08-11 16:30:00.051 -APP-   [scheduler-1] WARN c.some.package.class.method-98 - Configuration not present for configType:global or keysms.template Picking default value: 2 
  </code></pre>