The UIImagePickerController class manages customizable, system-supplied user interfaces for taking pictures and movies on supported devices, and for browsing saved images and movies for use in your app. An image picker controller manages user interactions and delivers the results of those interactions to a delegate object.
Opening an app within another app is managed in iOS through the "url scheme" mechanism. If an app defines an url scheme and this scheme is public, then we can use it to run the app. Basic rule is to first check that the device supports that scheme like we cannot make a phone call on an iPad because the phone app is not supported on iPad. If the scheme is supported then we can call it. This concept is used in making call through app.
In struts2 we can define validation using xml file. Struts2, for validation rules, has classes and all classes implements validator interface. Struts2 Action relies on a validation framework provided by XWork to enable the application of input validation rules to your Actions before they are executed. Struts2 Validation Framework allows us to separate the validation logic from actual Java/JSP code, where it can be reviewed and easily modified later.
The Contacts Database is divided into 3 tables which are contacts, raw contacts and data. Each table contains column (_ID) which is an auto incremented primary key. Data table contains all the contact information like phone number, mail id, address etc. User cannot add any data into contacts table. The data in this table is populated internally.