Kotlin Code Pills — Null Safe

One of the most common problem in many programming languages, like Java, is that while accessing an object of a null reference will result in a null reference exception. Kotlin aimed to solve this common NullReferenceException. Kotlin uses type inference.

In Kotlin, the type system distinguishes between references that can hold null (nullable references) and those that can not (non-null references).

For example, a regular variable of type String can not hold null

var a: String = "hello, world!"
a = null // compilation error

To allow nulls, we can declare a variable as a nullable string, written String?:

var b: String? = "hello, world!"
b = null // ok
print(b)

This makes the code more concise and gives more control while coding.

See you next coding pill.