title: log4j:WARN No such property [rollingPolicy] in org.apache.log4j.RollingFileAppender
body: <p>I am using log4j-1.2.16.jar and apache-log4j-extras-1.2.17.jar. </p>
  
  <p>I want to enable rolling files with date appended to the filename. But showing this errot and files are not rotating as expected.</p>
  
  <p>My log4j.properties file looks like this.</p>
  
  <pre><code>zookeeper.root.logger=DEBUG, ROLLINGFILE
  zookeeper.console.threshold=DEBUG
  zookeeper.log.dir=/path/to/logs
  zookeeper.log.file=zookeeper.log
  zookeeper.log.threshold=DEBUG
  zookeeper.tracelog.dir=.
  zookeeper.tracelog.file=zookeeper_trace.log
  log4j.appender.ROLLINGFILE=org.apache.log4j.RollingFileAppender
  log4j.appender.ROLLINGFILE.Threshold=${zookeeper.log.threshold}
  log4j.appender.ROLLINGFILE.File=${zookeeper.log.dir}/${zookeeper.log.file}
  log4j.appender.ROLLINGFILE.rollingPolicy=org.apache.log4j.rolling.TimeBasedRollingPolicy
  log4j.appender.ROLLINGFILE.rollingPolicy.fileNamePattern=${zookeeper.log.dir}/app%d{yyyy-MM-dd}.log
  log4j.appender.ROLLINGFILE.MaxFileSize=20KB
  log4j.appender.ROLLINGFILE.MaxBackupIndex=100000
  log4j.appender.ROLLINGFILE.layout=org.apache.log4j.PatternLayout
  log4j.appender.ROLLINGFILE.layout.ConversionPattern=%d{ISO8601} [myid:%X{myid}] - %-5p [%t:%C{1}@%L] - %m%n
  </code></pre>