Classes

Classes are the foundational type in Kotlin. In Kotlin, a class is a template that provides a state, a behavior, and a type to instances (more on that later).

To define a class, only a name is required:

class VeryBasic

VeryBasic is not very useful, but is still a valid Kotlin syntax.

The VeryBasic class doesn't have any state or behavior; nonetheless, you can declare values of type VeryBasic, as shown in the following code:

fun main(args: Array<String>) {
    val basic: VeryBasic = VeryBasic()
}

As you can see, the basic value has a VeryBasic type. To express it differently, basic is an instance of VeryBasic.

In Kotlin, types can be inferred; so, the previous example is equivalent to the following code:

fun main(args: Array<String>) {
    val basic = VeryBasic()
}

By being a VeryBasic instance, basic has a copy of the VeryBasic type's state and behavior, namely, none. So sad.