What is a data class in Kotlin?

We frequently create classes whose main purpose is to hold data. In Kotlin, this is called a data class and is marked as data:

data class User(val name: String, val age: Int)

To ensure consistency and meaningful behavior of the generated code, data classes have to fulfill the following requirements:

• The primary constructor needs to have at least one parameter;
• All primary constructor parameters need to be marked as val or var;
• Data classes cannot be abstract, open, sealed or inner;