<code>
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;

public void onValidate(String value) throws InvalidEmail {
    try {
        InternetAddress.parse(value);
    } catch (AddressException e) {
        throw new InvalidEmail("Email: "+value+" is invalid.  Try something like myname@myhost.com");
    }
}
</code>