There is the property http://apache.org/xml/properties/dom/current-element-node
which is very useful for determining error node during validation.
com.sun.org.apache.xerces.internal.impl.Constants.java has its definition but
comparing to original Xerces impl the
com.sun.org.apache.xerces.internal.jaxp.validation.ValidatorImpl.java
getProperty method lack of support of this property.

P.S. Actually there is a big problem to deal with found error. During validation
we have little information for good error handling. F.g. during in-memory DOM
validation we can get only hardcoded "strange" error message from the
SAXParseException).

I think the best way will be to change the ErrorHandler to the specialized
validation error handler like below:

public interface ValidationErrorHandler {

   public boolean handleError(ErrorInformation ei);
}
 
where handleError will return whether validator can continue validation and
ErrorInformation has error node, error message text.
It will be great to have access to the schema part(grammar part) responsible for
this error (f.g. using Schema Object Model).