Hi, this is a repost, and I'm sorry if I annoy anybody with it, but it's already a week and nobody replied yet (to what I think might be a serious issue for anybody using XML for configuration). Or might this be an issue for the developers list rather than this list and should i post it there? So here's again, what I have problems with: I've encountered some strange behaviour (bug?) in Drools (4.0.7) when adding packages from XML. Take the following rule as an example: <rule name="constraintTest"> <lhs> <pattern identifier="$foo" object-type="Bar" > <field-constraint field-name="a"> <literal-restriction evaluator="==" value="A" /> </field-constraint> <or-constraint-connective> <and-constraint-connective> <field-constraint field-name="b"> <literal-restriction evaluator="==" value="B" /> </field-constraint> <field-constraint field-name="c"> <literal-restriction evaluator="==" value="C" /> </field-constraint> </and-constraint-connective> <field-constraint field-name="d"> <literal-restriction evaluator="==" value="D" /> </field-constraint> </or-constraint-connective> </pattern> </lhs> <rhs> log("constraintTest"); </rhs> </rule> Trying to add a package from this gives the following Error: org.drools.compiler.DroolsParserException: org.xml.sax.SAXParseException: <or-constraint-connective> is after an invalid element: org.drools.xml.Handler at org.drools.compiler.PackageBuilder.addPackageFromXml(PackageBuilder.java:184) Now here's what's strange: If you rewrite the pattern like this <pattern identifier="$foo" object-type="Bar" > <or-constraint-connective> <and-constraint-connective> <field-constraint field-name="b"> <literal-restriction evaluator="==" value="B" /> </field-constraint> <field-constraint field-name="c"> <literal-restriction evaluator="==" value="C" /> </field-constraint> </and-constraint-connective> <field-constraint field-name="d"> <literal-restriction evaluator="==" value="D" /> </field-constraint> </or-constraint-connective> <field-constraint field-name="a"> <literal-restriction evaluator="==" value="A" /> </field-constraint> </pattern> in other words (and I tried this with a couple of variations), if you put all field-constraints after any and-constraint-connectives or or-constraint-connectives sharing the same parent element, the package adds just fine. I couldn't find any reason, why this should be intended behaviour, so I assume it's a bug. I took a little peek into Drools' source, and my guess is, that there's just some 'validPeers' missing in one of the *Handler classes that are responsible for the validation of Drools XML configuration files. However, this really is just my first guess. 'Adds just fine' is not the whole truth though: Modifying the pattern as described above, still leaves me with the following message (strangely printed to stdout, instead of using a logger or throwing an exception): (null: 33, 46): cvc-complex-type.2.4.a: Invalid content starting with element 'field-constraint'. One of '{"http://drools.org/drools-4.0":and-constraint-connective}' is expected. Now, if I wrap the "d" field-constraint (see my example) into an and-constraint-connective (and thus being the field-constraint the only element in the and-constraint-connective, which looks rather useless), that message goes away. Even more oddness: the "a" field-constraint doesn't cause such a message - even without a wrapping it into an and-constraint-connective. Many thanks in advance, Paul