My web application on google app engine was built using jdk 1.7 and eclipse. The project worked fine on the localhost server and so i deployed to the cloud using eclipse tool. The issue is that the application instead of being deployed to [my_app_id].appspot.com gets deployed at 1-dot-[my_app_id].appspot.com
Now i can access the application on 1-dot-[my_app_id].appspot.com but thats not the pid i wish to have.I have double checked the project id and i haven't added any 1-dot before my app id. My actual [my_app_id].appspot.com displays just a Hello World page, which is not getting updated even on using mvn appengine:update.
Please suggest if i have made any mistake while deployment.

The behavior you mention suggests that your app version 1 was correctly deployed, but it's not the default version (see Routing via URL).
In the Google Cloud Platform console, on the versions page, you should see the deployed versions. Just make the version 1 the default one (or switch traffic to it).
By default when deploying using the gcloud SDK the new version becomes the default one (but that can be changed). For example, from gcloud app deploy:
But I'm not familiar with Eclipse, I don't know if/how its GAE plugin can be configured to automatically make the deployed version the default one.