JoranConfigurator configurator = new JoranConfigurator();
configurator.setContext(context);
context.reset();
configurator.doConfigure(u);
@SuppressWarnings({ "rawtypes", "unchecked" })
HashMap<String, Appender<?>> appenderBag = (HashMap) configurator
		 .getInterpretationContext()
		 .getObjectMap().get(ActionConst.APPENDER_BAG);
for (Appender<?> a : appenderBag.values()) {
	System.out.println("Rolling file for " + a.getName());
	if (a instanceof RollingFileAppender) {
		System.out.println("really Rolling file for " + a.getName());
		try {
			((RollingFileAppender<?>)a).rollover();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

java.lang.NullPointerException
	at ch.qos.logback.core.rolling.helper.FileFilterUtil.afterLastSlash(FileFilterUtil.java:46)
	at ch.qos.logback.core.rolling.TimeBasedRollingPolicy.rollover(TimeBasedRollingPolicy.java:149)
	at ch.qos.logback.core.rolling.RollingFileAppender.attemptRollover(RollingFileAppender.java:158)
	at ch.qos.logback.core.rolling.RollingFileAppender.rollover(RollingFileAppender.java:137)
	at config.log.LoggerUtils.loadLoggingConfig(LoggerUtils.java:73)
	at config.ProjectContextListener.contextInitialized(ProjectContextListener.java:52)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4973)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5467)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
	at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:672)
	at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1862)
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

  <appender name="warnings-to-file" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <filter class="config.log.ActionMarkerFilter">
      <OnMatch>DENY</OnMatch>
      <OnMismatch>NEUTRAL</OnMismatch>
    </filter>
    <filter class="config.log.TimingMarkerFilter">
      <OnMatch>DENY</OnMatch>
      <OnMismatch>NEUTRAL</OnMismatch>
    </filter>
    <file>${LOG_PATH}/warnings.log</file>
    <encoder>
        <pattern>%d{HH:mm:ss}	%-4level	%msg%n</pattern>
    </encoder>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
        <fileNamePattern>${LOG_PATH}/warnings-%d{yyyy-MM-dd}.%i.log</fileNamePattern>
        <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
            <maxFileSize>100MB</maxFileSize>
            <elapsedPeriodsFileName>warnings.log</elapsedPeriodsFileName>
        </timeBasedFileNamingAndTriggeringPolicy>
    </rollingPolicy>
  </appender>