public  void error(String domain,
    String key,
    XMLParseException exception) throws XNIException
Reports an error. Errors are non-fatal and usually signify that the
document is invalid with respect to its grammar(s).

 public  void fatalError(String domain,
    String key,
    XMLParseException exception) throws XNIException
Report a fatal error. Fatal errors usually occur when the document
is not well-formed and signifies that the parser cannot continue
normal operation.

Note: The error handler should always
throw an XNIException from this method. This exception
can either be the same exception that is passed as a parameter to
the method or a new XNI exception object. If the registered error
handler fails to throw an exception, the continuing operation of
the parser is undetermined.

 public  void warning(String domain,
    String key,
    XMLParseException exception) throws XNIException
Reports a warning. Warnings are non-fatal and can be safely ignored
by most applications.