奇怪的 throws exception

org.springframework.mail.MailSender

void send(SimpleMailMessage simpleMessage) throws MailException;

private static JavaMailSender mailSender = null;

 mailSender = (JavaMailSender) xxx;

public static void sendMail(SimpleMailMessage msg)

    {

        mailSender.send(msg);

    }

为什么sendMail不需要catch exception  或者 throw出去？

[code]
public abstract class MailException extends NestedRuntimeException {
[/code]
不懂的看源码能解决很多问题，这个是运行期异常，可以不用try catch