When persistent="false", still need kahadb jar file?

[acec acec]

After I upgraded activemq 5.4.1, I got the the following exception:
...
nested exception is java.lang.NoClassDefFoundError: 
org/apache/kahadb/page/Transaction$Closure
...

My activemq configuration :
<broker xmlns="http://activemq.apache.org/schema/core"; useJmx="false" 
persistent="false">
        <transportConnectors>
            <transportConnector name="tcp" uri="${activemq.brokerURL}"/>
        </transportConnectors>
    </broker>

The persistent has been disabled, why activemq still call kahadb class?

Thanks.