Thanks *Michael for the immediate response.* ** *Yes.The rule has been defined in guided web editor.* ** *I had taken sample respoitory ( Pricing Loan guided web editor rules) and added the negate option in the row-1 of the rules and Validating the rules throws the error posted earlier.* ** *Here is the source of the rule-1 , * ** 1. | #from row number: 1 2. | rule "Row 1 Pricing loans" 3. | dialect "mvel" 4. | when 5. | not ( 6. | application : LoanApplication( amount > "131000" , amount <= "200000" , lengthYears == "30" , deposit < "20000" ) 7. | income : IncomeSource( type == "Asset" ) 8. | ) 9. | then 10. | application.setApproved( true ); 11. | application.setInsuranceCost( 0 ); 12. | application.setApprovedRate( 2 ); 13. | end Regards, Mahmood *From:* mahmood lebbai <mahmoodlebbai(a)yahoo.com&gt; *To:* &quot;rules-users(a)lists.jboss.org&quot; <rules-users(a)lists.jboss.org&gt; *Sent:* Saturday, 21 May 2011 2:55 PM *Subject:* DROOLS Negate Question I need help to clarify the following I had taken latest Guvnour 5.2.0 M2 version and use the sample pricing loan rules. When i tried to use the "Negate" Meta data option and set it to true on first rule , i had got the following error. Pricing loans] [ERR 102] Line 7:3 mismatched input 'income' in rule "Row 1 Pricing loans" [Pricing loans] Line 16:0 unexpected exception at input 'rule'. Exception: java.util.EmptyStackException. Stack trace: java.util.EmptyStackException at java.util.Stack.peek(Stack.java:79) at java.util.Stack.pop(Stack.java:61) at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:409) at org.drools.lang.ParserHelper.end(ParserHelper.java:723) at org.drools.lang.DRLParser.rule(DRLParser.java:915) at org.drools.lang.DRLParser.statement(DRLParser.java:248) at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:143) at org.drools.compiler.DrlParser.compile(DrlParser.java:225) at org.drools.compiler.DrlParser.parse(DrlParser.java:71) at org.drools.compiler.DrlParser.parse(DrlParser.java:76) at I have a similar requirement where in I need to write both negate with true and false within the same ruleset in guvnour. Please help me out how to achieve this. Regards, Mahmood _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users