Kotlin Programming MCQ for Competitive Exams, Interviews, and Certifications

31

Kotlin has two equality operators, == and ===. What is the difference?

A) == determines if two primitive types are identical. === determines if two objects are identical B) == determines if two references point to the same object. === determines if two objects have the same value C) == determines if two objects have the same value. === determines if two strings have the same value D) == determines if two objects have the same value. === determines if two references point to the same object

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

32

Your code need to try casting an object. If the cast is not possible, you do not want an exception generated, instead you want null to be assigned. Which operator can safely cast a value?

A) as? B) ?? C) is D) as

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

33

Which is the correct declaration of an integer array with a size of 5?

A) val arrs[5]: Int B) val arrs = IntArray(5) C) val arrs: Int[5] D) val arrs = Array<Int>(5)

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

34

Which command will return the length of a String in Kotlin?

A) str.length B) length(str) C) str.lengthOf D) str.getLength()

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

35

Which view attribute do you use to set the width of a View so that it adjusts to fit the content?

A) android:view_width="wrap" B) android:layout_width="wrap_content" C) android:layout_height="wrap_content" D) android:layout_width="match_parent"

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

36

You would like to group a list of students by last name and get the total number of groups. Which line of code accomplishes this, assuming you have a list of the Student data class? Data class Student(val firstName: String, val lastName: String)

A) Println(students.groupBy{ it.lastName }.count()) B) Println(students.groupBy{ it.lastName.first() }.fold().count()) C) Delegates.rx() D) Println(students.groupingBy{ it.lastName.first() }.size())

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

37

Which method changes the image resource for an ImageView in Kotlin code?

A) setImageResource() B) setImageURI() C) setImage() D) setImageRes()

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

38

Which of the following extension methods are used in Kotlin?

A) Read texts () & Headlines () B) Buffer reader () C) Read each line () D) All of the above

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

39

Which method on an Activity inflates the app's layout and makes its views available as objects?

A) onCreate() B) setClickListener() C) setContentView() D) show

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

40

Which is the correct way to reference bound data in the XML layout?

A) android:text="@={myDataClass.property}" B) android:text="@={myDataClass}" C) android:text="@={myDataClass.property.string}" D) android:text="@={myDataClass.bound_data.property}"

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board