Google AppEngine

• Google App Engine enables you to build and host web apps on the same systems that power Google applications. App Engine offers fast development and deployment; simple administration, with no need to worry about hardware, patches or backups; and effortless scalability

• App Engine applications are easy to build.

• Easy to maintain.

• Easy to scale as your traffic and data storage needs grow.

Why Developers chose It…..?????

Pricing:

• Each application costs just $8 per user, per month up to a maximum of $1000 a month. Pay only for what you use.

• An application on a free account can use up to 500MB of storage and up to 5 million page views a month. When you are ready for more, you can enable billing.

Google Vs Amazon

• If your application can be architected to run within the limited Google App Engine runtime environment, then take advantage of Google's lower hosting costs.

• If you need a more flexible cloud deployment platform, then AWS is a good fit for your needs.

Google Vs Azure

• In Google AppEngine we don't pay until our app grows quite a bit. With Azure, you pay almost $100 each month, even if you don't have a single website visitor. If your db goes over 1GB, we have to pay extra for it.

Cont…

• GAE has the lightest admin load. Once you're setup, deploying and re-deploying is quick and they'll auto-everything. For example, you don't worry about how many servers your app is using, how to share the data, how to load-balance.

Cont…

• GAE lets you have multiple versions of your application running on the same datastore. You can deploy, test a version and then set the current 'live' version when you're ready. You can change back if something goes wrong.

Supported Languages:

• Google App Engine supports two languages

– Python

– Java

Java

• We can build web applications using standard Java technologies and run them on Google's scalable infrastructure.

Java RunTime Environment:

• App Engine runs Java applications using the Java 6 virtual machine (JVM). The App Engine SDK supports Java 5 and later, and the Java 6 JVM can use classes compiled with any version of the Java compiler up to Java 6.

Storage:

• App Engine provides scalable services that apps can use to store persistent data, access resources over the network, and perform other tasks like manipulating image data.

• Apps can use the App Engine Datastore for reliable, scalable persistent storage of data. The datastore supports 2 standard Java interfaces:– Java Data Objects (JDO)

– Java Persistence API (JPA)

Storage(cont…)

• The App Engine Memcache provides fast, transient distributed storage for caching the results of datastore queries and calculations. The Java interface implements JCache.

• Apps use the URL Fetch service to access resources over the web, and to communicate with other hosts using the HTTP and HTTPS protocols. Java apps can simply use java.net.URLConnection and related classes from the Java standard library to access this service

The Bottom Line

• The datastore is more difficult to use than a relational database (which for example has global transactions, joins on tables, and a subset of the types of queries that you can do with a relational database). Not being able to start and manage long-running processes also makes some kinds of applications difficult to write

How to Deploy a java Application

• Java RunTime Environment• Install the Eclipse• Add the Google plugins• Create an account on Google App engine• Create a unique key for Applications• Create an Application• Deploy on the Google App Engine

Plug-in

• Plugin for eclipse 3.5– http://dl.google.com/eclipse/plugin/3.5

• Hello World Demo