FULL PRODUCT VERSION :
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Ver 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
set a LSResourceResolver to the SchemaFactory and Validator won't work.

            SchemaFactory fact = ...
            fact.setResourceResolver(new LSResourceResolver() {
                        public LSInput resolveResource(String type,
                                                       String namespaceURI,
                                                       String publicId,
                                                       String systemId,
                                                       String baseURI) {
                            System.out.println("---- ---- FACTORY ---- ----");
                            System.out.println("type = " + type);
                            System.out.println("namespaceURI = " +
                                               namespaceURI);
                            System.out.println("publicId = " + publicId);
                            System.out.println("systemId = " + systemId);
                            System.out.println("baseURI = " + baseURI);
                            System.out.println("---- ---- ---- ----");
                            return null;
                        }
                    });
            Validator val = JaxpValidatorDelegator.newValidator();
            val.setResourceResolver(new LSResourceResolver() {
                        public LSInput resolveResource(String type,
                                                       String namespaceURI,
                                                       String publicId,
                                                       String systemId,
                                                       String baseURI) {
                            System.out.println("---- ---- VALIDATOR ---- ----");
                            System.out.println("type = " + type);
                            System.out.println("namespaceURI = " +
                                               namespaceURI);
                            System.out.println("publicId = " + publicId);
                            System.out.println("systemId = " + systemId);
                            System.out.println("baseURI = " + baseURI);
                            System.out.println("---- ---- ---- ----");
                            return null;
                        }
                    });
            val.validate(new StreamSource(file));

the result doesn't contain any message. but if I use Xerces 2.9.1(org.apache.xerces.jaxp.validation.XMLSchemaFactory)
 I got the message like:

---- ---- VALIDATOR ---- ----
type = http://www.w3.org/2001/XMLSchema
namespaceURI = http://www.example.com/IPO/address
publicId = null
systemId = addressv2.xsd
baseURI = file:///D:/Workspace/Zone/JAXP_Validation/commons_jaxp_validation/po/ipov2.xsd
---- ---- ---- ----

It seems that the default one in JDK5(com.sun.org.apache.xerces.internal.jaxp.validation.xs.SchemaFactoryImpl) do not support setResourceResolver(LSResourceResolver resourceResolver).

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
It should print out the message like:
---- ---- VALIDATOR ---- ----
type = http://www.w3.org/2001/XMLSchema
namespaceURI = http://www.example.com/IPO/address
publicId = null
systemId = addressv2.xsd
baseURI = file:///D:/Workspace/Zone/JAXP_Validation/commons_jaxp_validation/po/ipov2.xsd
---- ---- ---- ----

ACTUAL -
Nothing printed out.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Using Xerces 2.9.1.