kotlin-stdlib / kotlin.collections / AbstractMutableMap / <init> <init> protected AbstractMutableMap() Provides a skeletal implementation of the MutableMap interface. The implementor is required to implement entries property, which should return mutable set of map entries, and put function. Parameters K - the type of map keys. The map is invariant on its key type. V - the type of map values. The map is invariant on its value type.