The documentation merely tells that returning false is enaught to fail parsing, but nothing is told about exceptions/messages shown to user. In my case, I've got the java source code of the validator at the console output. This nosense is OK, as the parser does not know anything about semantic validation, hardly it can provide any reason of the failure to the user. Please tell, what is a typical action to cease parsing of an input file, when we discover it has a wrong version?