Comments on: Google App Engine for Java Demo Application

By: Jeff Douglas

Jeff Douglas — Tue, 12 Apr 2011 21:52:46 +0000

Siva, it uses the web services api therefore the credentials are hardcoded into the app.

By: Siva

Siva — Wed, 30 Mar 2011 03:55:51 +0000

Something is very wrong. I just realized that there is no login method or some kind of credentials even to authenticate, leave aside the error in any file in the project.

By: Siva

Siva — Wed, 30 Mar 2011 03:34:16 +0000

Can you please help me with running this? So far, this is what I have done.

I downloaded your project zip, imported it into eclipse and used ‘Run> Debug As> WebApplication’. The server started. But when I navigate to http://localhost:8888 (which is where it said it started the server), I get the following error. Can’t able to find which part of the code is generating it.

and this is what I got.

HTTP ERROR 500

Problem accessing /telesales. Reason:

INTERNAL_SERVER_ERROR

Caused by:

java.lang.NullPointerException
at com.jeffdouglas.TelesalesServlet.doGet(TelesalesServlet.java:26)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:58)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:351)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

By: Brian Boelsterli

Brian Boelsterli — Sun, 14 Nov 2010 02:09:04 +0000

Hi Jeff,
I’m plowing through your book “Beginning Java Google App Engine”. Im having trouble figuring out where the code is. Especially starting with Chapter 4. I’ve plowed through the book about 10 times now and all I see is a reference to the google app engine sdk. Unfortunately, there is no code there. Please advise. Thanks!

By: leslie

leslie — Thu, 28 Oct 2010 08:40:51 +0000

i am new in learn GAE for java. but i have a problem with jdo
would u help me

By: Belman

Belman — Sat, 03 Apr 2010 16:24:22 +0000

Hi Sir Jeff,
Thank you for sharing this demo app.
This helped me a lot in my project using GAE for Java.

By: jeffdonthemic

jeffdonthemic — Thu, 13 Aug 2009 12:08:54 +0000

I haven’t noticed anything yet but I’ll definitely take a look. Thanks for the heads up.

By: Thomas Lukasik

Thomas Lukasik — Thu, 13 Aug 2009 11:22:27 +0000

I’ve had an issue with some of my code that recently stopped working (a simple query does not return any data) since upgrading to the latest GAE SDK and Eclipse plugin. In an attempt to troubleshoot the problem I ran your Telesales example on 2 different workstations – one where my code works and one where it has stopped working. Your Telesales example seems to exhibit the same behavior, working on the earlier SDK and not working with the latest one. Have you experienced anything like this?

By: Donnie Demuth

Donnie Demuth — Fri, 31 Jul 2009 23:04:09 +0000

Thank goodness. I’ll probably be able to put something up today or tomorrow after playing with your app! I wish some of this was covered in GAE-J’s reference docs. I really appreciate the time you put in to share your app.

By: James

James — Tue, 09 Jun 2009 21:53:26 +0000

Hi Jeff

What a great little project – this is just what I needed to get me going.

Thanks – you’re a live saver, great blog btw!

James