debug is not saving under debug.log

I have created an application using log4j using xml configuration, the applications saves logs based on levels,..ierror logs to error.log, info logs to info.log.

The application is working fine but debug logs is not saving under debug.log file. rest all logs are saving correctly

can anyone please tell me some solution for this

My log4jConfig.xml is as given below

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://ift.tt/1jdUINB">

    <appender name="debug-out" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="${openfireHome}/logs/debug.log" />
        <param name="MaxFileSize" value="1024KB"/>
        <param name="MaxBackupIndex" value="5"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d [%t] %-7p %10c{1} - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="debug" />
            <param name="LevelMin" value="debug" />
            <param name="AcceptOnMatch" value="true" />
        </filter>
    </appender>

    <appender name="info-out" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="${openfireHome}/logs/info.log" />
        <param name="MaxFileSize" value="1024KB"/>
        <param name="MaxBackupIndex" value="5"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d [%t] %-7p %10c{1} - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="info" />
            <param name="LevelMin" value="info" />
            <param name="AcceptOnMatch" value="true" />
        </filter>
    </appender>

    <appender name="warn-out" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="${openfireHome}/logs/warn.log" />
        <param name="MaxFileSize" value="1024KB"/>
        <param name="MaxBackupIndex" value="5"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d [%t] %-7p %10c{1} - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMax" value="warn" />
            <param name="LevelMin" value="warn" />
            <param name="AcceptOnMatch" value="true" />
        </filter>
    </appender>

    <appender name="error-out" class="org.apache.log4j.RollingFileAppender">
        <param name="File" value="${openfireHome}/logs/error.log" />
        <param name="MaxFileSize" value="1024KB"/>
        <param name="MaxBackupIndex" value="5"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d [%t] %-7p %10c{1} - %m%n" />
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="error" />
            <param name="AcceptOnMatch" value="true" />
        </filter>
    </appender>

    <root>
        <level value="info" />
        <appender-ref ref="debug-out" />
        <appender-ref ref="info-out" />
        <appender-ref ref="warn-out" />
        <appender-ref ref="error-out" />
    </root>
</log4j:configuration>

StartupListener.java

package com.log4jdemo;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.log4j.xml.DOMConfigurator;

public class StartupListener implements ServletContextListener
{
    @Override
    public void contextInitialized(ServletContextEvent event)
    {
        ServletContext servletContext = event.getServletContext();
        System.setProperty("openfireHome", servletContext.getRealPath("/"));

        Logger logger = null;
        String log4jFile = servletContext.getInitParameter("log4jConfig");
        System.out.println(log4jFile);
        DOMConfigurator.configure(log4jFile);
        logger = LogManager.getLogger(StartupListener.class.getName());
        logger.debug("Loaded: " + log4jFile);

        logger.info("This is a logging statement from log4j");
        logger.debug("Show DEBUG message");
        logger.info("Show INFO message");
        logger.warn("Show WARN message");
        logger.error("Show ERROR message");
        logger.fatal("Show FATAL message");
        System.out.println(servletContext.getRealPath("/")+"/WEB-INF/logs/");
    }

    @Override
    public void contextDestroyed(ServletContextEvent arg0)
    {

    }
}