Hi I have a rule using xml. <!-- 1st Rules For Field objects--> <rule name="Rule1"> <lhs> <pattern identifier="outterMap" object-type="HashMap" /> <pattern identifier="innerMap" object-type="HashMap"> <from> <expression>outterMap.get("fact")</expression> </from> </pattern> <pattern identifier="field" object-type="Filterable"> <from> <expression>innerMap.get("filterable")</expression> </from> </pattern> <pattern identifier = "document" object-type="Document"> <from> <expression> field.getDocument();")</expression> </from> </pattern> <eval> document.getIsNormalTask()</eval> </lhs> <rhs> field.setDefaultOptionality(Boolean.TRUE); </rhs> </rule> Another Rule is <!-- 2 nd Rule for Menu Items--> <rule name="Rule2"> <lhs> <pattern identifier="outterMap" object-type="HashMap" /> <pattern identifier="innerMap" object-type="HashMap"> <from> <expression>outterMap.get("fact")</expression> </from> </pattern> <pattern identifier="editMode" object-type="Boolean"> <from> <expression>innerMap.get("editMode")</expression> </from> </pattern> <pattern identifier="menuItem" object-type="Filterable"> <from> <expression>innerMap.get("filterable")</expression> </from> </pattern> <pattern identifier = "document" object-type="Document"> <from> <expression> menuItem.getDocument();")</expression> </from> </pattern> <eval>editMode==true &amp;&amp; !document.isInDraftStatus()</eval> </lhs> <rhs> menuItem.setDefaultVisibility((Boolean)true); </rhs> </rule> The total classes that I have are: Filterable.java Field.java inherits Filterable (contains Document object) MenuItem.java inherits Filterable (contains Document object) Document.java I am setting up the filter based on rule name such that for MenuItems rule executed is : Rule2 For Field objects rule executed is :Rule1 The problem is that all the rules are executed for all the objects passed as facts and statements above <lhs> are matched. As these are diffrent, runtime error is displayed that error in Rule1, getOptionality for field producing error. Basically I want to know should lhs be the same for all the rules in the Rule Base? And why are all the patterns matched for a given fact in working memory? Thanks -- View this message in context: http://www.nabble.com/Should-lhs-pattern-be-the-same-for-diffrent-Rules-i... Sent from the drools - user mailing list archive at Nabble.com.