[rules-users] Is this syntax correct?

I need to fire a rule if I have more then one fact that has an endDate property from the last 24 months... is the follwoing correct? rule "testing123" when olList: ArrayList(size > 1) from collect(CreditEventLocal(creditEventTypeVlId == "SOMETHING", $endDate: endDate -> ($endDate.after(DateUtils.addMonthsFromToday(-24))))) then System.out.println("eurika"); end Anyhow, if it is then I get a NullPointerException which doesn't tell me what the problem is. It happens in building time of course: I'm using drools4.0.0MR2 Exception in thread "main" java.lang.NullPointerException at org.drools.rule.builder.dialect.java.JavaConsequenceBuilder.build(JavaConsequenceBuilder.java:53) at org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:65) at org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:353) at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:233) at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:157) at com.emi.framework.antTasks.PackageRules.addPackages(PackageRules.java:227) at com.emi.framework.antTasks.PackageRules.execute(PackageRules.java:143) at com.emi.framework.antTasks.PackageRules.main(PackageRules.java:325)