Google App Engine(1)Java Start and Installation
Installing the Java SDK
We develop and upload Java applications for Google App Engine using the App Engine java software development kit(SDK).

Getting Java
Our application is running on App Engine, but App Engine is based on JVM and standard libraries. I am an old Java user, so I already have Java.

Using Eclipse and the Google Plugin for Eclipse
Install the eclipse plugin
https://dl.google.com/eclipse/plugin/4.2

Using Apache ANT
ANT is a must for me an old Java man.

Getting the SDK
I am using Eclipse and Google Plugin. Click on the References--Google--App Engine
It installed a 1.7.4 App Engine under my eclipse.
The directory is very deep in my local machine, I do not like that. So I try to install it my self. Get the package in this URL.
https://developers.google.com/appengine/downloads#Google_App_Engine_SDK_for_Java

appengine-java-sdk-1.7.4.zip

Unzip the file and place it in the working directory
>pwd
/Users/carl/tool/appengine-java-sdk-1.7.4
>sudo ln -s /Users/carl/tool/appengine-java-sdk-1.7.4 /opt/appengine-java-sdk-1.7.4
>sudo ln -s /opt/appengine-java-sdk-1.7.4 /opt/appengine-java

Change the Eclipse -- Google -- App Engine to point to here.

Append the path export PATH=/opt/appengine-java/bin:$PATH in ~/.profile
>. ~/.profile

Trying a Demo Application
>cd /opt/appengine-java/demos/guestbook
>dev_appserver.sh war

Then I can visit 2 web URLs
http://localhost:8080/
That is the sample and demo of guestbook.

http://localhost:8080/_ah/admin
That is the console admin.


References:
https://developers.google.com/appengine/docs/java/gettingstarted/