To get started with Google App Engine Java SDK, normally you can read the fundamentals from Google's Documents. For someone, it may make you hard to start coding.Some of documents are:
I think it's better to "learning by doing" in this situation. Make some install --> do hello world --> get to know Google app Engine later.

Now, Let's get started with installing Java SDK and Google Plugin for Eclipse.

Step 1 : Install Java SE development KIT (SDK)

After download and install SDK, type: 
 java - version 
to verify that you can run this command, and confirm which version is installed. (For Windows, type in command prompt, for MAC and Linux in terminal )
I'm using Java SDK 1.6
You've installed Java SDK, now turn to step 2 , to get Eclipse and install Google Plugin for Eclipse 

Step 2: Get Eclipse and install Google Plugin for Eclipse 

I prefer Eclipse for coding, because eclipse can be extended by installing plugins. (For me, i installed Pydev in Eclipse for Python, Aptana Plugin for HTML, CSS, JS, PHP, native Eclipse for Java . There are some popular Google Plugin versions belong to each Eclipse version:
  1. The Google Plugin for Eclipse, for Eclipse 3.8/4.2 (Juno): https://dl.google.com/eclipse/plugin/4.2
  2.  The Google Plugin for Eclipse, for Eclipse 3.7 (Indigo): https://dl.google.com/eclipse/plugin/3.7
  3. The Google Plugin for Eclipse, for Eclipse 3.6 (Helios): https://dl.google.com/eclipse/plugin/3.6
  4. The Google Plugin for Eclipse, for Eclipse 3.5 (Galileo): https://dl.google.com/eclipse/plugin/3.5
  5. The Google Plugin for Eclipse, for Eclipse 3.4 (Ganymede): https://dl.google.com/eclipse/plugin/3.4
- To install new Plugin for Eclipse. At the menu bar, click on : Help/Install new Software . The following Available software will occur:

Paste one of the Google Plugin url written above to  "type or select a site" input form , and click Add.

give it any name you want for management. For me, I simple use "Google Plugins", click OK and wait...
check any features you want. I just develop Web version of GAE for now, so I checked to install:
  • Google Plugin for Eclipse : it's required, of course ^^
  • GWT Designer for GPE
  • SDKs: it include Google App Engine Java SDK (newest version) and Google Web Toolkit SDK
for Android developer, other things in that list are essential. 
Click next --> Agree with license and waiting for installing .... 

 Restart Eclipse and you can see Google services and Development tools in your Eclipse now.


Let's keep up with GAE now by turning to  "Getting first Google app engine app with slim3 framework"