Generator hours counter

2015-10-20 17:45:44.204 [ERROR] [.o.m.r.i.engine.ExecuteRuleJob] - Error during the execution of rule Increment Generator Runtimes
java.lang.RuntimeException: The name 'java' cannot be resolved to an item or type.

And this is the full script:

var org.joda.time.DateTime whenStarted = null

rule "Generator started"
when
    Item Generator received command ON
then
    whenStarted = now
end

rule "Generator stopped"
when
    Item Generator received command OFF
then
    if(whenStarted != null) {
        // do the same as the if(Generator.state == ON && whenStarted != null) in the increment rule
    }
    whenStarted = null
end

rule "Increment Generator Runtimes"
when
    Time cron "* */1 * * * ?"
then
    if(Generator.state == ON && whenStarted != null){
        logInfo("GenUptime", "Getting now")
        val long nowMsec = now.millis

        logInfo("GenUptime", "Getting whenStarted")
        val long wsMsec = whenStarted.millis

        logInfo("GenUptime", "Resetting whenStarted")
        whenStarted = now

        logInfo("GenUptime", "Calculating time difference")
        val long timeSinceLastUpdate = nowMsec - wsMsec

        logInfo("GenUptime", "Getting total Uptime in msec")
        val long oldVal = if(GeneratorRuntimeMSec.state == Undefined || GeneratorRuntimeMSec.state == Uninitialized) 0 else (GeneratorRuntimeMSec.state as Number).longValue

        logInfo("GenUpTime", "Adding current time to total: timeSinceLastUpdate = " + timeSinceLastUpdate + " oldVal = " + oldVal)
        val long totalMsec = oldVal + timeSinceLastUpdate // calculate total runtime<F2>

        logInfo("GenUptime", "Posting totalMsec to Item")
        GeneratorRuntimeMSec.postUpdate(totalMsec) // post the full runtime

        logInfo("GenUptime", "Calculating hours")
        val long hours = java.lang.Math.round(totalMsec/1000/60/60)

        logInfo("GenUptime", "Posting hours")
        GeneratorRuntimeHours.postUpdate(hours)
    }
    else if(Generator.state == ON && whenStarted == null){
        logInfo("GenUptime", "Generator is ON but Generator started rule never executed")
        whenStarted = now
    }
    else {
        logInfo("GenUptime", "Generator is not running")
    }
end