Kotlin Kotlin Extensions and Delegates 3

Question 1

How do you check if a `lateinit var` has been initialized in Kotlin?

Accepted Answer

Using `::property.isInitialized`

Answer

By using a try-catch around the access

Answer

By checking `property != null`

Answer

There is no way to check

Question 2

What is a receiver in the context of Kotlin extension functions?

Accepted Answer

The object on which the extension function is called, accessible as `this`

Answer

The return value of the function

Answer

The parameter list of the function

Answer

The class that defines the extension

Question 3

Can extension functions be defined on nullable types in Kotlin?

Accepted Answer

Yes, using `fun Type?.functionName()` syntax

Answer

No, extensions cannot be defined on nullable types

Answer

Yes, but only for data classes

Answer

Yes, but they must return nullable values

Question 4

What is a DSL in Kotlin and how are extension functions used to build them?

Accepted Answer

A Domain-Specific Language built using extension functions and lambdas with receivers for readable configuration code

Answer

A debugging syntax layer

Answer

A database query language

Answer

A test framework

Question 5

What is a lambda with receiver in Kotlin?

Accepted Answer

A lambda where `this` is bound to the specified receiver type, enabling DSL-like code

Answer

A lambda that returns the receiver object

Answer

A lambda that takes a receiver as a parameter

Answer

A lambda defined inside an extension function

Question 6

What is the `infix` keyword used for in Kotlin?

Accepted Answer

Allowing a function to be called without parentheses using infix notation

Answer

Defining operator overloads

Answer

Marking a function as inline

Answer

Defining a function that works on two types