INFO5126 Quiz #1

Question 1

Who developed Kotlin?

Answer 1

JetBrains

Question 2

How does Kotlin compile to native code?

Answer 2

LLVM

Question 3

What are the 5 reasons to use Kotlin? (Can’t Sell In The Nude)

Answer 3

1. Concise
2. Safe
3. Interoperable
4. Tool Friendly
5. No checked exceptions

Question 4

Why is Kotlin considered safe?

Answer 4

Avoids entire classes of errors like Null Pointer Exception

Question 5

Which keyword is used for read only variables?

Answer 5

val

Question 6

Which keyword is used for mutable variables?

Answer 6

var

Question 7

How do you perform string interpolation?

Answer 7

$ and { }

Question 8

How do you test that two variables refer to the same object?

Answer 8

===

Question 9

What keyword is used for switch statements?

Answer 9

when

Question 10

What is the Elvis operator?

Answer 10

?:

Question 11

What operator is used to return the non-null type value and throw an exception if the value is null?

Answer 11

!!
val l = b!!.length

Question 12

What operator returns the expression on the left if not null and the expression on the right if null?

Answer 12

?:
val l = b?.length ?: 1

Question 13

How do you filter out non-null elements from a collection of Nullable type?

Answer 13

filterNotNull()

Question 14

What function instantiates an immutable list?

Answer 14

listOf()

Question 15

What function instantiates a mutable list?

Answer 15

mutableListOf()

Question 16

What keyword is used to declare a function?

Answer 16

fun

Question 17

Class member functions are ________

Answer 17

virtual

Question 18

Class members are ________ by default

Answer 18

public

Question 19

Classes are ________ by default

Answer 19

final

Question 20

If a class member is not initialized during construction what keyword do you use to initialize it?

Answer 20

lateinit

Question 21

What keyword is used to create a Singleton?

Answer 21

object

Question 22

What keyword is used for static methods?

Answer 22

companion

Question 23

What is view binding a subset of?

Answer 23

Data Binding

Question 24

In most cases view binding replaces what function?

Answer 24

findViewById()

Question 25

What file do you change to enable view binding?

Answer 25

Gradle Module

Question 26

What function is used with view binding to give direct reference to the root view of the corresponding layout file?

Answer 26

getRoot()

Question 27

What does ViewBinding change the IDs of the XML layout file to?

Answer 27

camelCase

Question 28

What library did we use for JSON with Kotlin?

Answer 28

GSON

Question 29

What kind of class should you use when working with JSON?

Answer 29

data

Question 30

What keyword should you use to make data class field names different from the JSON names?

Answer 30

@SerializedName(“key_name”)

Question 31

How do you parse a class object into JSON using GSON?

Answer 31

Gson().toJson(Object)