I'm doing this: ThermostatTimeData ttd1 = new ThermostatTimeData("January", "Monday", 14); session.insert(ttd1); WorkDays wd = new WorkDays(); session.insert(wd); session.fireAllRules(); printoutThermostatData(ttd1); and then this: rule "Rule 1" when $wd : com.sample.WorkDays() $ttd : ThermostatTimeData ( day memberOf $wd ) then modify ( $ttd ) { setDaytype("workday") } System.out.println("Rule 1 fired."); end And I get the error like in subject. Anybody knows why? WorkDays.java: package com.sample; import java.util.ArrayList; import java.util.List; public class WorkDays { private List<String> wd; public WorkDays() { this.wd = new ArrayList<String>(); this.wd.add("Monday"); this.wd.add("Tuesday"); this.wd.add("Wednesday"); this.wd.add("Thursday"); this.wd.add("Friday"); } public List<String> getWorkDays() { return this.wd; } } _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users