Top 10 Kotlin Interview questions

Basically, strings refer to a collection of various characters altogether. There are two types of strings present in Kotlin which are-

• Raw strings
• Escaped strings

Under these strings, templates can also be evaluated easily and this evaluation is known by term as string template interpolation.

Data types are the instances of consonants or variables tending to decide the type of variable. It also specifies the space required for the storage of these variables.

The data types are-

• Numbers
• Characters
• Strings
• Arrays
• Booleans

Note: This is one of the significant kotlin interview questions asked in most interviews.

There are two types of constructors in Kotlin which are-

• Primary constructor- It is a specific section of class header and mostly it is always declared after the class name.
• Secondary constructor- This section of the constructor is always declared inside the class.

Inline Functions

Used to prevent the object allocations for the functions or lambda expressions that have been called.

Infix Functions

It is used for calling functions without any parentheses or brackets.

If you give default values to all the primary constructor values, you shall automatically create an empty constructor for data class.

For example, if you have a data class like this:

data class Activity(
   var updated_on: String,
   var tags: List,
   var description: String,
   var user_id: List,
)

And you want to initialize the data class with an empty constructor, all you have to do is assign the default values to all the primary constructors, like this:

data class Activity(
   var updated_on: String = "",
   var tags: List = emptyList(),
   var description: String = "",
   var user_id: List = emptyList(),
)

Here’s how to initialize an array in Kotlin.

In Kotlin, you should use var where the value of the variable is changing very frequently. A good example would be getting the location of an android device: var integerVariable : Int? = null

Whereas, Val should be used in a case where there would be no change of value throughout the whole class. For example, setting the value of text view or maybe a button’s text through code:

val stringVariables : String = "Button's Final Text"

Here is the best way to create a singleton class in Kotlin:

In Kotlin, if you need to write a code for a function that can be called without a class instance but it needs access to the internals of a class, you can use a companion object declaration in that specific class.

Null safety, also known as void safety is a guarantee that no object references shall have null or void values.

Nullable types in Kotlin are a type of reference which are declared by putting a “?” behind the String.