Java 8 has reached end of support
and will be deprecated
on January 31, 2026. After deprecation, you won't be able to deploy Java 8
applications, even if your organization previously used an organization policy to
re-enable deployments of legacy runtimes. Your existing Java
8 applications will continue to run and receive traffic after their
deprecation date. We recommend that
you migrate to the latest supported version of Java.
Receiving Bounce Notification
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To receive email bounce notifications, you need to configure your app to enable bounce notification and you need to handle the incoming notification in your app.
Configuring your application for email bounce notification
By default, applications do not receive bounce notifications for email that
could not be delivered. To enable the incoming bounce notification service, you
must modify your application appengine-web.xml and web.xml configuration
files.
Modify appengine-web.xmlby adding an inbound-services section to enable the
incoming bounce service:
<inbound-services>
<!--Usedtohandleincomingmail.-->
<service>mail</service>
<!--Usedtohandlebouncedmailnotifications.-->
<service>mail_bounce</service>
</inbound-services>Modify web.xml by mapping the bounce URL /_ah/bounce to your bounce
handling servlet, as follows:
<servlet>
<servlet-name>bouncehandler</servlet-name>
<servlet-class>com.example.appengine.mail.BounceHandlerServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>bouncehandler</servlet-name>
<url-pattern>/_ah/bounce</url-pattern>
</servlet-mapping>
<security-constraint>
<web-resource-collection>
<web-resource-name>bounce</web-resource-name>
<url-pattern>/_ah/bounce</url-pattern>
</web-resource-collection>
<auth-constraint>
<role-name>admin</role-name>
</auth-constraint>
</security-constraint>Handling Bounce Notifications
The JavaMail API includes the BounceNotificationParser class, which you use to parse incoming bounce notifications, as shown here:
importcom.google.appengine.api.mail.BounceNotification ;
importcom.google.appengine.api.mail.BounceNotificationParser ;
importjava.io.IOException;
importjava.util.logging.Logger;
importjavax.mail.MessagingException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
publicclass BounceHandlerServletextendsHttpServlet{
privatestaticfinalLoggerlog=Logger.getLogger(BounceHandlerServlet.class.getName());
@Override
publicvoiddoPost(HttpServletRequestreq,HttpServletResponseresp)throwsIOException{
try{
BounceNotification bounce=BounceNotificationParser .parse(req);
log.warning("Bounced email notification.");
// The following data is available in a BounceNotification object
// bounce.getOriginal().getFrom()
// bounce.getOriginal().getTo()
// bounce.getOriginal().getSubject()
// bounce.getOriginal().getText()
// bounce.getNotification().getFrom()
// bounce.getNotification().getTo()
// bounce.getNotification().getSubject()
// bounce.getNotification().getText()
// ...
}catch(MessagingExceptione){
// ...
}
}
}