Dealing with nulls

Handling nulls is a critical aspect of Kotlin programming, especially when interfacing with Java libraries or databases. Kotlin provides several tools to deal with nullability in a safe and expressive way.

Kotlin supports traditional null checks similar to Java:

val stringOrNull: String? = if (Random.nextBoolean()) "String" else null
 
if (stringOrNull != null) {
    println(stringOrNull.length)
}

This approach is straightforward but can lead to verbose code, especially with nested null checks.

The Elvis operator offers a concise way to handle null values by providing a default value:

val alwaysLength = stringOrNull?.length ?: 0

If stringOrNull is not null, alwaysLength will be its length; otherwise, it defaults to 0.

For nested objects with nullable properties, chaining null-safe calls prevents receiving a NullPointerException:

data class Response(val profile: UserProfile?)
data class UserProfile(val firstName: String...