Validators for modularized family of XML Schemas

Hello all,

I've got a modularized family of XML Schemas for a new RuleML release:
http://www.ruleml.org/0.86/xsd.

XSV (http://www.w3.org/2001/03/webdata/xsv) accepts them fine, but other
validators seem not to.  I'd like to confirm that they are valid by using
other well-known validators/tools such as SQC and XML Spy.  This may be of
value to modular schema systems in general, most prominently XHTML. Does
anyone have experience with validating such modular systems of XSDs?

One example of validation inconsistencies I found is as follows:
 
SQC returns a java.lang.NullPointerException and the following error
messages (the whole thing is appended below):

ERROR
SEVERITY: 2
ERROR TYPE: 1
MESSAGE
unknown exception in Xerces
------------------------------------------------------------------------
ERROR
 file = file:C:/RuleML/0.86/xsd/urdatalog.xsd line -1 column -1
SEVERITY: 1
ERROR TYPE: 1
MESSAGE
null

Any help in diagnosing these inconsistent validation results would be
greatly appreciated, as well as pointers to other modularized families of
schemas.

David

***

Initializing Schema Quality Checker. Please wait ...
SchemaQualityChecker has been initialized
PROCESSING ..\..\0.86\xsd\urdatalog.xsd time : 2004-06-30T19:02:05 ...
..\..\0.86\xsd\urdatalog.xsd (file 1 of 1) now being read ...
java.lang.NullPointerException
        at java.util.Arrays$ArrayList.<init>(Unknown Source)
        at java.util.Arrays.asList(Unknown Source)
        at
com.ibm.xml.ecm.schema.impl.AttributeGroupDefImpl.getEffectiveAttribu
teDecls(Unknown Source)
        at
com.ibm.xml.ecm.schema.impl.AttributeGroupDefImpl.getCheckers(Unknown
 Source)
        at
com.ibm.sketch.parser.Util.runCheckersNeverActivateInInteractiveMode(
Unknown Source)
        at
com.ibm.sketch.schemaparser.Redefine_ATTRIBUTEGROUPDEF_ElementHandler
.mainEndElement(Unknown Source)
        at com.ibm.sketch.parser.S_Dispatcher.endElement(Unknown Source)
        at com.ibm.sketch.parser.S_Dispatcher.endElement(Unknown Source)
        at com.ibm.sketch.parser.S_Dispatcher.endElement(Unknown Source)
        at
com.ibm.sketch.schemaparser.XSDParserImpl$SimpleSchemaDocumentHandler
Impl.endElement(Unknown Source)
        at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown
Source
)
        at com.ibm.sketch.connection.PassThroughFilter.endElement(Unknown
Source
)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.endElement(Unknown
Sourc
e)
        at
org.apache.xerces.impl.XMLNamespaceBinder.handleEndElement(Unknown So
urce)
        at org.apache.xerces.impl.XMLNamespaceBinder.endElement(Unknown
Source)
        at
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanEndElement(
Unknown Source)
        at
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContent
Dispatcher.dispatch(Unknown Source)
        at
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Un
known Source)
        at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
        at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
        at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
        at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
        at
com.ibm.sketch.schemaparser.XSDParserImpl.parseInternalSubsetWithErro
rChecking(Unknown Source)
        at
com.ibm.sketch.schemaparser.XSDParserImpl$ValidationVisitor.parse(Unk
nown Source)
        at
com.ibm.sketch.schemaparser.XSDParserImpl$ValidationVisitor.visitVert
ex(Unknown Source)
        at com.ibm.sketch.graph.DepthFirstTraversal.traverse(Unknown Source)
        at com.ibm.sketch.graph.DepthFirstTraversal.traverse(Unknown Source)
        at com.ibm.sketch.schemaparser.XSDParserImpl.parse(Unknown Source)
        at com.ibm.sketch.schemaparser.XSDParserImpl.parse(Unknown Source)
        at
com.ibm.xml.ecm.schema.impl.OpenCloseManagerImpl.getSchemasLocatedAt(
Unknown Source)
        at com.ibm.sketch.utilities.Lint.findErrors(Unknown Source)
        at com.ibm.sketch.util.SchemaQualityChecker.process(Unknown Source)
        at com.ibm.sketch.util.SchemaQualityChecker.process(Unknown Source)
        at
com.ibm.sketch.util.CommandLineApplication.processFromCommandLine(Unk
nown Source)
        at com.ibm.sketch.util.SchemaQualityChecker.main(Unknown Source)
ERROR
SEVERITY: 2
ERROR TYPE: 1
MESSAGE
unknown exception in Xerces

   ------------------------------------------------------------------------
ERROR
 file = file:C:/RuleML/0.86/xsd/urdatalog.xsd line -1 column -1
SEVERITY: 1
ERROR TYPE: 1
MESSAGE
null

   ------------------------------------------------------------------------
end time = 2004-06-30T19:02:09

Received on Wednesday, 30 June 2004 19:30:10 UTC