Technology Questions

The app delegate object is created by UIApplicationMain function at app launch time. The app delegate object's main job is to handle state transitions within the app.

The knowledge of Joins is a MUST for every interviewee. Most SQL programmers have used inner join and  outer join[left/right]; but the catch point here is to also mention cross join and self-join.

Optimized code tends to run faster and make more efficient use of the system’s resources. Optimized codes are also less susceptible to errors and take lesser space in memory and in file size.

- Multi-threading fetching in Amazon S3 is used to fetch the objects concurrently using the multiple threads and map the task so that fetching can be made simpler. 

- It is not a good practice to increase the threading for a particular object as every node on the server has some bandwidth constraints. 

- It provides user the ease with which they can upload the files and upload the threads in parallel. 

- It provides high speed of data transfer and easy maintenance of the sever as well.

These objects provide two levels of scope:

Application State

Data stored in the application object can be shared by all the sessions of the application.

Application object stores data in the key value pair.

All the above listed actions are the functions of cursor

Yes the object is retained. It creates a timer that calls a selector on the current threads run loop. It may not be 100% precise time-wise as it attempts to dequeue the message from the run loop and perform the selector.