title: How logback is formatting spring boot logs, in predefined json format?
body: <p>New to spring boot. </p>
  
  <p>I have seen, when including the <code>logback-spring.xml</code>, it makes the spring boot to emit the logs in json format to stdout.</p>
  
  <p><em>logback.xml:-</em></p>
  
  <pre><code>&lt;appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender"&gt;
      &lt;encoder&gt;
          &lt;charset&gt;UTF-8&lt;/charset&gt;
          &lt;pattern&gt;%msg%n&lt;/pattern&gt;
      &lt;/encoder&gt;
  &lt;/appender&gt;
  
  &lt;logger name="com.verizon" level="INFO" additivity="false"&gt;
      &lt;appender-ref ref="consoleAppender" /&gt;      
  &lt;/logger&gt;
  </code></pre>
  
  <p>Sample Log from console:-</p>
  
  <pre><code>{"created_date":"2019-01-03T15:31:47.499","log_level":"INFO","thread":"main","logger":"package name.classname goes here","desc":"Started SupportApplication in 60.031 seconds (JVM running for 63.974)"}
  </code></pre>
  
  <p>My questions is,</p>
  
  <ol>
  <li>Which base class is having these created_date,log_level,INFO,logger,desc properties?</li>
  <li>Is it possible to override the above base class to customize those properties?</li>
  <li>Is logback actively listening the stdout console to capture the info "Started SupportApplication in XX seconds......"?</li>
  </ol>
  
  <p>I tried to look around <code>ch.qos.logback.core.ConsoleAppender</code> class, but unable to find the solution to above questions.</p>
  
  <p>Could some one provide inputs here.</p>