In Kotlin classes are:
- Public by default
- Final by default
To let the coder inherit from a class we have to use the keyword open. The same applies to methods:
open class Employee {
open fun doSomething() { // can be overridden
}
}
Construction parameters are provided in the class definition. This is the primary constructor. (Internally, Kotlin provides a getter and/or a setter wheter the parameter is a val or a var)
open class Employee(val name : String) {
}
Secondary constructor:
open class Employee(val name : String) {
constructor(name: String, id : Int) : this(name)
}
Constructors and inheritance :
class Tester(name : String) : Employee(name) {
}
More about classes here
miniguide 