If Alert plugin is disabled, below exception can be raised:

com.pmease.quickbuild.plugin.measurement.core.poller.MeasurementDataHandler.onReceivedMeasurements(java.util.List)]
    java.lang.reflect.InvocationTargetException
        at sun.reflect.GeneratedMethodAccessor220.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
        at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
        at com.google.common.eventbus.EventBus.dispatch(EventBus.java:313)
        at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
        at com.google.common.eventbus.EventBus.post(EventBus.java:267)
        at com.pmease.quickbuild.plugin.measurement.core.poller.MeasurementPollingTask.execute(MeasurementPollingTask.java:56)
        at com.pmease.quickbuild.plugin.measurement.core.poller.MeasurementPollingTask.run(MeasurementPollingTask.java:108)
        at com.google.common.util.concurrent.AbstractExecutionThreadService$1$1.run(AbstractExecutionThreadService.java:52)
        at java.lang.Thread.run(Unknown Source)
    Caused by: java.lang.NullPointerException
        at com.pmease.quickbuild.plugin.measurement.core.poller.MeasurementDataHandler.getAlertDefinitions(MeasurementDataHandler.java:143)
        at com.pmease.quickbuild.plugin.measurement.core.poller.MeasurementDataHandler.evaluteAlerts(MeasurementDataHandler.java:63)
        at com.pmease.quickbuild.plugin.measurement.core.poller.MeasurementDataHandler.onReceivedMeasurements(MeasurementDataHandler.java:50)
        ... 12 more