HCLTech Senior Android Application Developer Interview Questions and Answers

Encryption and decryption in Swift involves using cryptographic algorithms to encode and decode data securely.

• Use common encryption algorithms like AES or RSA for encryption.

• Implement encryption using libraries like CommonCrypto or CryptoSwift.

• Store encryption keys securely and use secure protocols for data transmission.

• Example: Encrypting a string using AES encryption in Swift.

Keychain access in Swift allows secure storage of sensitive information like passwords, tokens, etc.

• Use Keychain Services API to securely store and retrieve sensitive data.

• Keychain items are stored securely in the device's keychain and are encrypted.

• Access keychain items using unique identifiers called keys.

• Use Keychain Swift library for easier implementation.

Classes are reference types, while structs are value types in Swift.

• Classes are reference types, meaning they point to the same instance in memory when assigned to a new variable.

• Structs are value types, meaning they create a new copy when assigned to a new variable.

• Use classes for complex data structures or when you need inheritance, use structs for simple data types or when you want value semantics.

• Example: class Per...read more

Grand Central Dispatch (GCD) is a technology in Swift for managing concurrent operations.

• GCD allows developers to perform tasks concurrently without having to manage threads manually.

• It provides a high-level API for managing tasks and executing them on different queues.

• Developers can use GCD to perform tasks in the background, update the UI on the main thread, and more.

Struct is a value type, Class is a reference type in Swift.

• Structs are passed by value, Classes are passed by reference.

• Structs are immutable by default, Classes are mutable.

• Use Structs for simple data types, Classes for more complex objects.

A closure is a self-contained block of code that can be passed around and used in your code. An escaping closure is a closure that is called after the function it was passed to has returned.

• Closure is a block of code that can be passed around and used in your code.

• Escaping closure is called after the function it was passed to has returned.

• Example: Using a completion handler in a network request to handle the response a

Multi threading is the ability of a CPU to execute multiple threads concurrently, allowing for improved performance and responsiveness in applications.

• Allows for parallel execution of tasks, improving performance

• Enables applications to remain responsive while performing intensive tasks

• Can lead to synchronization issues if not managed properly

ARC (Automatic Reference Counting) in Swift is a memory management system used to automatically manage memory allocation and deallocation.

• ARC keeps track of how many references there are to an object and automatically deallocates it when there are no more references.

• Use strong reference cycles can lead to memory leaks, so use weak or unowned references to break the cycle.

• ARC is the default memory management system in S...read more

MVVM (Model-View-ViewModel) is an architectural design pattern commonly used in iOS development to separate concerns and improve code maintainability.

• MVVM separates the user interface (View) from the business logic (ViewModel) and data (Model).

• ViewModel acts as an intermediary between the View and the Model, handling user interactions and updating the data.

• Swift provides tools like Combine framework for reactive progra...read more