18 Null Safety questions from the Kotlin bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
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A.a type marked with a trailing question mark that is permitted to hold a null reference
B.the ?: syntax that supplies a fallback value when the left expression evaluates to null
C.the !! syntax that forces a value to non-null and throws an exception if it is actually null
D.a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
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2. Which term means: "a type marked with a trailing question mark that is permitted to hold a null reference"?
Junior
A.let scope function for nulls
B.Elvis operator
C.Safe call operator
D.Nullable type
Answer + AI explanation with Pro
3. Which statement is correct?
Junior
A.Nullable type — the ?. syntax that returns null instead of throwing when the receiver is absent
B.Nullable type — a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark
C.Nullable type — a type marked with a trailing question mark that is permitted to hold a null reference
D.Nullable type — the !! syntax that forces a value to non-null and throws an exception if it is actually null
Answer + AI explanation with Pro
4. What is Safe call operator?
Junior
A.a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
B.the ?. syntax that returns null instead of throwing when the receiver is absent
C.a type marked with a trailing question mark that is permitted to hold a null reference
D.the !! syntax that forces a value to non-null and throws an exception if it is actually null
Answer + AI explanation with Pro
5. Which term means: "the ?. syntax that returns null instead of throwing when the receiver is absent"?
Junior
A.let scope function for nulls
B.Platform type
C.Elvis operator
D.Safe call operator
Answer + AI explanation with Pro
6. Which statement is correct?
Junior
A.Safe call operator — a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark
B.Safe call operator — a type marked with a trailing question mark that is permitted to hold a null reference
C.Safe call operator — a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
D.Safe call operator — the ?. syntax that returns null instead of throwing when the receiver is absent
Answer + AI explanation with Pro
7. What is Elvis operator?
Mid
A.the ?: syntax that supplies a fallback value when the left expression evaluates to null
B.a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark
C.a type marked with a trailing question mark that is permitted to hold a null reference
D.a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
Answer + AI explanation with Pro
8. Which term means: "the ?: syntax that supplies a fallback value when the left expression evaluates to null"?
Mid
A.Nullable type
B.let scope function for nulls
C.Elvis operator
D.Safe call operator
Answer + AI explanation with Pro
9. Which statement is correct?
Mid
A.Elvis operator — a type marked with a trailing question mark that is permitted to hold a null reference
B.Elvis operator — a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
C.Elvis operator — the !! syntax that forces a value to non-null and throws an exception if it is actually null
D.Elvis operator — the ?: syntax that supplies a fallback value when the left expression evaluates to null
Answer + AI explanation with Pro
10. What is Not-null assertion operator?
Mid
A.a type marked with a trailing question mark that is permitted to hold a null reference
B.a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
C.the ?. syntax that returns null instead of throwing when the receiver is absent
D.the !! syntax that forces a value to non-null and throws an exception if it is actually null
Answer + AI explanation with Pro
11. Which term means: "the !! syntax that forces a value to non-null and throws an exception if it is actually null"?
Mid
A.Not-null assertion operator
B.Nullable type
C.let scope function for nulls
D.Elvis operator
Answer + AI explanation with Pro
12. Which statement is correct?
Mid
A.Not-null assertion operator — the !! syntax that forces a value to non-null and throws an exception if it is actually null
B.Not-null assertion operator — the ?. syntax that returns null instead of throwing when the receiver is absent
C.Not-null assertion operator — a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark
D.Not-null assertion operator — the ?: syntax that supplies a fallback value when the left expression evaluates to null
Answer + AI explanation with Pro
13. What is let scope function for nulls?
Mid
A.the ?. syntax that returns null instead of throwing when the receiver is absent
B.a type marked with a trailing question mark that is permitted to hold a null reference
C.a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
D.the !! syntax that forces a value to non-null and throws an exception if it is actually null
Answer + AI explanation with Pro
14. Which term means: "a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter"?
Mid
A.Nullable type
B.Elvis operator
C.Safe call operator
D.let scope function for nulls
Answer + AI explanation with Pro
15. Which statement is correct?
Mid
A.let scope function for nulls — a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
B.let scope function for nulls — the ?: syntax that supplies a fallback value when the left expression evaluates to null
C.let scope function for nulls — a type marked with a trailing question mark that is permitted to hold a null reference
D.let scope function for nulls — the ?. syntax that returns null instead of throwing when the receiver is absent
Answer + AI explanation with Pro
16. What is Platform type?
Senior
A.the ?: syntax that supplies a fallback value when the left expression evaluates to null
B.a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark
C.a type marked with a trailing question mark that is permitted to hold a null reference
D.a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
Answer + AI explanation with Pro
17. Which term means: "a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark"?
Senior
A.Platform type
B.let scope function for nulls
C.Safe call operator
D.Elvis operator
Answer + AI explanation with Pro
18. Which statement is correct?
Senior
A.Platform type — the !! syntax that forces a value to non-null and throws an exception if it is actually null
B.Platform type — a type coming from Java whose nullability is unknown to the compiler, shown with an exclamation mark
C.Platform type — the ?. syntax that returns null instead of throwing when the receiver is absent
D.Platform type — a call combined with the safe operator that runs a block only when the receiver is non-null, exposing it as a parameter
Answer + AI explanation with Pro
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