title: slf4j not logging in DEBUG.log with log.debug(...)
body: <p>I have problem with slf4j, logging at info and warning level works. But logging at debug level doesn't. I checked under debugger and log.isDebugEnabled() is true, so log.debug("INPUT:\n" + input) is executing but DEBUG.log is empty. I enabled in my IntelliJ IDE option "Enable debug output" (it adds VM option -Ddebug) and it still doen't work.</p>
  
  <pre><code>(..)
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  (..)
  public class LoginController {
  
      private static final Logger log = LoggerFactory.getLogger(LoginController.class);
  
      public AuthUser login(InputStream inputStream, HttpServletRequest    request) throws Exception {
  
        final String input = misc.InputStreamToString(inputStream);
        if (log.isDebugEnabled()) {
          log.debug("INPUT:\n" + input);
       }
  
       (..)
     }
  </code></pre>
  
  <p><strong>Update 1:</strong></p>
  
  <p>file resources/logback.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;configuration&gt;
  
  &lt;property name="HOME" value="${user.dir}/logs"/&gt;
  
  &lt;appender name="FILE-INSERT-DEBUG"
            class="ch.qos.logback.core.rolling.RollingFileAppender"&gt;
      &lt;filter class="ch.qos.logback.classic.filter.LevelFilter"&gt;
          &lt;level&gt;DEBUG&lt;/level&gt;
          &lt;onMismatch&gt;DENY&lt;/onMismatch&gt;
      &lt;/filter&gt;
  
      &lt;file&gt;${HOME}/DEBUG.log&lt;/file&gt;
      &lt;encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder"&gt;
          &lt;Pattern&gt;
              %d{yyyy-MM-dd HH:mm:ss} - %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;${HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log.zip
          &lt;/fileNamePattern&gt;
          &lt;timeBasedFileNamingAndTriggeringPolicy
                  class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"&gt;
              &lt;maxFileSize&gt;10MB&lt;/maxFileSize&gt;
          &lt;/timeBasedFileNamingAndTriggeringPolicy&gt;
      &lt;/rollingPolicy&gt;
  
  &lt;/appender&gt;
  
  &lt;appender name="FILE-INSERT-INFO"
            class="ch.qos.logback.core.rolling.RollingFileAppender"&gt;
      &lt;filter class="ch.qos.logback.classic.filter.LevelFilter"&gt;
          &lt;level&gt;INFO&lt;/level&gt;
          &lt;onMatch&gt;ACCEPT&lt;/onMatch&gt;
          &lt;onMismatch&gt;DENY&lt;/onMismatch&gt;
      &lt;/filter&gt;
      &lt;file&gt;${HOME}/INFO.log&lt;/file&gt;
      &lt;encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder"&gt;
          &lt;Pattern&gt;
              %d{yyyy-MM-dd HH:mm:ss} - %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;${HOME}/archived/INFO.%d{yyyy-MM-dd}.%i.log.zip
          &lt;/fileNamePattern&gt;
          &lt;timeBasedFileNamingAndTriggeringPolicy
                  class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"&gt;
              &lt;maxFileSize&gt;10MB&lt;/maxFileSize&gt;
          &lt;/timeBasedFileNamingAndTriggeringPolicy&gt;
      &lt;/rollingPolicy&gt;
  
  &lt;/appender&gt;
  
  &lt;appender name="FILE-INSERT-WARN"
            class="ch.qos.logback.core.rolling.RollingFileAppender"&gt;
      &lt;filter class="ch.qos.logback.classic.filter.LevelFilter"&gt;
          &lt;level&gt;WARN&lt;/level&gt;
          &lt;onMatch&gt;ACCEPT&lt;/onMatch&gt;
          &lt;onMismatch&gt;DENY&lt;/onMismatch&gt;
      &lt;/filter&gt;
      &lt;file&gt;${HOME}/WARN.log&lt;/file&gt;
      &lt;encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder"&gt;
          &lt;Pattern&gt;
              %d{yyyy-MM-dd HH:mm:ss} - %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;${HOME}/archived/WARN.%d{yyyy-MM-dd}.%i.log.zip
          &lt;/fileNamePattern&gt;
          &lt;timeBasedFileNamingAndTriggeringPolicy
                  class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"&gt;
              &lt;maxFileSize&gt;10MB&lt;/maxFileSize&gt;
          &lt;/timeBasedFileNamingAndTriggeringPolicy&gt;
      &lt;/rollingPolicy&gt;
  
  &lt;/appender&gt;
  
  &lt;appender name="FILE-INSERT-ERROR"
            class="ch.qos.logback.core.rolling.RollingFileAppender"&gt;
      &lt;filter class="ch.qos.logback.classic.filter.LevelFilter"&gt;
          &lt;level&gt;ERROR&lt;/level&gt;
          &lt;onMatch&gt;ACCEPT&lt;/onMatch&gt;
          &lt;onMismatch&gt;DENY&lt;/onMismatch&gt;
      &lt;/filter&gt;
      &lt;file&gt;${HOME}/ERROR.log&lt;/file&gt;
      &lt;encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder"&gt;
          &lt;Pattern&gt;
              %d{yyyy-MM-dd HH:mm:ss} - %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;${HOME}/archived/ERROR.%d{yyyy-MM-dd}.%i.log.zip
          &lt;/fileNamePattern&gt;
          &lt;timeBasedFileNamingAndTriggeringPolicy
                  class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"&gt;
              &lt;maxFileSize&gt;10MB&lt;/maxFileSize&gt;
          &lt;/timeBasedFileNamingAndTriggeringPolicy&gt;
      &lt;/rollingPolicy&gt;
  
  &lt;/appender&gt;
  &lt;root level="DEBUG"&gt;
      &lt;!--&lt;appender-ref ref="FILE-INSERT-DEBUG" /&gt;--&gt;
      &lt;appender-ref ref="FILE-INSERT-INFO"/&gt;
      &lt;appender-ref ref="FILE-INSERT-WARN"/&gt;
      &lt;appender-ref ref="FILE-INSERT-ERROR"/&gt;
  &lt;/root&gt;
  &lt;/configuration&gt;
  </code></pre>