Kotlin Kotlin Type System and Null Safety 2

Question 1

Which keyword is used to check if an object is of a specific type in Kotlin?

Accepted Answer

is

Answer

The `is` operator checks whether an object is an instance of a given type, similar to Java's `instanceof`.

Question 2

What does the unsafe cast operator `as` do when the object is not of the target type?

Accepted Answer

Throws ClassCastException

Answer

The unsafe cast operator `as` throws a `ClassCastException` at runtime if the object cannot be cast to the specified target type.

Question 3

What does the safe cast operator `as?` return when the cast is unsuccessful?

Accepted Answer

null

Answer

The safe cast operator `as?` returns null instead of throwing an exception when the object cannot be cast to the target type.

Question 4

What keyword defines a type alias in Kotlin?

Accepted Answer

typealias

Answer

The `typealias` keyword creates an alternative name for an existing type, improving readability for complex type signatures.

Question 5

What is the `Nothing` type in Kotlin primarily used for?

Accepted Answer

Functions that always throw or loop infinitely

Answer

`Nothing` represents a value that never exists; it's the return type of functions like `throw` expressions or infinite loops that never complete normally.

Kotlin Practice Test

Kotlin Practice Test

Kotlin Kotlin Type System and Null Safety 2