Interview Q&A

Short answer: Real Use Cases Validation frameworks Logging metadata Role-based security API documentation metadata Custom Attribute Example [AttributeUsage(AttributeTargets.Property)] public class RequiredAttribute : Attribute {} Usage Example public class Employee

Example code

{ [Required] public string Name { get; set; }
} Validation Logic public static void Validate(object obj)
{
var properties = obj.GetType().GetProperties();
foreach (var prop in properties)
{
var isRequired = prop.GetCustomAttributes(typeof(RequiredAttribute), false).Any();
if (isRequired && prop.GetValue(obj) == null) throw new Exception($"{prop.Name} is required"); }
}

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Interface Meaning Defines capability and behavior contract Use when: Multiple inheritance is required System uses plug-in extensibility Loose coupling is necessary public interface IPayment { void Pay(decimal amount); } Abstract Class Meaning Provides base behavior with shared implementation Represents IS-A inheritance relationship public abstract class PaymentBase

Example code

{
public void Log() => Console.WriteLine("Payment logged");
public abstract void Pay(decimal amount);
} Summary Interface = Capability Abstract Class = Shared Base Behavior

Real-world example (ShopNest)

Answer with: definition → one ShopNest-style story → trade-off → how you would verify it in production.

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1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: bstract Class Meaning Provides base behavior with shared implementation Represents IS-A inheritance relationship public abstract class PaymentBase { public void Log() => Console.WriteLine("Payment logged"); public abstract void Pay(decimal amount); } Summary Interface = Capability bstract Class = Shared Base Behavior bstract Class Meaning Provides base… behavior with shared implementation Represents IS-A inheritance…

Explain a bit more

relationship public abstract class PaymentBase { public void Log() => Console.WriteLine("Payment logged"); public abstract void Pay(decimal amount); } Summary Interface = Capability bstract Class = Shared Base Behavior

Real-world example (ShopNest)

Answer with: definition → one ShopNest-style story → trade-off → how you would verify it in production.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: [ApiController] [Route("api/[controller]")] public class EmployeeController : ControllerBase { [HttpGet("{id}")] public IActionResult Get(int id)

Example code

{
return Ok(new { Id = id, Name = "Sandeep" });
}
} Key Characteristics: Lightweight JSON support by default Built-in dependency injection

Real-world example (ShopNest)

Answer with: definition → one ShopNest-style story → trade-off → how you would verify it in production.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Incorrect (not thread-safe) public class Singleton

Example code

{
private static Singleton _instance;
} Correct using double-check locking public sealed class Singleton
{
private static Singleton _instance;
private static readonly object _lock = new object();
private Singleton() {}
public static Singleton Instance
{ get {
if (_instance == null)
{ lock(_lock) {
if (_instance == null)
_instance = new Singleton();
}
}
return _instance;
}
}
} Best and simplest public sealed class Singleton
{
public static readonly Singleton Instance = new Singleton();
private Singleton(){}
}

Real-world example (ShopNest)

Answer with: definition → one ShopNest-style story → trade-off → how you would verify it in production.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A Git repository that does not have a working directory, typically used as a central remote repository (e.g., on a server).

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1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: llowing you to switch branches and come back to them later.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

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1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Temporarily saves changes that are not ready to be committed, allowing you to switch branches and come back to them later.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: commit, typically done during an interactive rebase.

Real-world example (ShopNest)

Prefer clear commits: fix(cart): prevent negative quantities instead of update.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Combining multiple commits into a single, more meaningful commit, typically done during an interactive rebase.

Real-world example (ShopNest)

Prefer clear commits: fix(cart): prevent negative quantities instead of update.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: The default name for the remote repository from which a project was originally cloned.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A pointer to the current commit you are on in your local repository.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A configuration file that stores user-specific Git settings (e.g., username, email, aliases).

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Shows changes between the staging area and the last commit.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Displays the commit history of the current branch.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Allows you to interactively stage specific parts (hunks) of changes within a file.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Shows the URLs of the remote repositories associated with your local repo.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: performing a binary search on the commit history.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A command used to find the commit that introduced a bug by performing a binary search on the commit history.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Checks the integrity of the Git file system.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Cleans up unnecessary files and optimizes the local repository.

Real-world example (ShopNest)

ShopNest’s team uses GitHub PRs with reviews and CI checks so broken builds never reach production unnoticed.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A merge where the branch being merged can simply be moved forward to the tip of the other branch without creating a new merge commit.

Real-world example (ShopNest)

Feature work for “UPI payment” lives on feature/upi-payment. Open a PR to main; resolve conflicts before merge.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: simply be moved forward to the tip of the other branch without creating a new merge commit.

Real-world example (ShopNest)

Feature work for “UPI payment” lives on feature/upi-payment. Open a PR to main; resolve conflicts before merge.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: common ancestor to determine how to combine changes, potentially creating a new merge commit. Long Answers:

Real-world example (ShopNest)

Feature work for “UPI payment” lives on feature/upi-payment. Open a PR to main; resolve conflicts before merge.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A merge that involves the two branch tips and their common ancestor to determine how to combine changes, potentially creating a new merge commit. Long Answers:

Real-world example (ShopNest)

Feature work for “UPI payment” lives on feature/upi-payment. Open a PR to main; resolve conflicts before merge.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.