I'm new to drools, so hopefully I can post enough information to get some help. We are running Drools 5.3.3.Final (though we've seen the same issue with 5.4.0.Final and 5.3.0.Final) I'm trying to test some rules created in drl format. Here's an example of a drl that executes fine – it checks a birthday field against a date literal: ------------------------------------------ package drools.rules.funnelid.two import com.infusionsoft.bpm.services.TestRuleFact; rule "Test Rule" dialect "java" when $testRuleFact : TestRuleFact( ( contactable.contact.birthday < "29-Dec-1977" ) ) then $testRuleFact.setTrue( ); end ------------------------------------------- However, this drl fails compilation with the following error: package drools.rules.funnelid.two import com.infusionsoft.bpm.services.TestRuleFact; rule "Test Rule" dialect "java" when $testRuleFact : TestRuleFact( ( contactable.contact.title str[equals] "Owner" && contactable.contact.birthday < "01-Jan-1980" ) || ( contactable.contact.country str[equals] "USA" && contactable.contact.leadSourceIdOverride == "12" ) ) then $testRuleFact.setTrue( ); End ------------------------------------------ Here's the error I get: DRL contains errors, no actions will be processed: Unable to Analyse Expression str0.evaluate( contactable.contact.title, "Owner" ) && contactable.contact.birthday < "01-Jan-1980" || str1.evaluate( contactable.contact.country, "USA" ) && contactable.contact.leadSourceIdOverride == "12": [Error: Comparison operation requires compatible types. Found class java.util.Date and class java.lang.String] [Near : {... ) && contactable.contact.leadSourceIdOverride == "12" ....}] ^ [Line: 8, Column: 32] : [Rule name='Test Rule'] Some things that cause the error to go away: * Removing the offending clause: contactable.contact.birthday < "01-Jan-1980" * Changing the || to an && I'm at a loss and would love some help. Even if I knew which class was raising the exception would help, but I can't seem to find it anywhere. Thanks, Eric