After a quick search, I found this StackOverflow thread about 'Cannot find symbol' error which discusses in detail how this error is related to the identifiers.
It seems that your actual issue is related to debugging your application. For further assistance I would recommend posting a question to StackOverflow <http://stackoverflow.com/questions/tagged/google-app-engine> which we also monitor, as this falls outside the scope of the issue tracker which is intended for issue reports and feature request. Check out our community support page <https://support.google.com/cloud/answer/3466163?hl=en> for the list of tags <https://cloud.google.com/support/docs/stackexchange> we monitor. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-appengine+unsubscr...@googlegroups.com. To post to this group, send email to email@example.com. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/874d5ccd-f2cc-48f1-a6d9-54191d979c94%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.