Person.kt

<!-- Copyright 2019 Google LLC.
SPDX-License-Identifier: Apache-2.0 -->

class Person(name: String, lastname: String) {
   var name: String = name
       set(value) {
           field = value.toLowerCase().capitalize()
           updateCount++
       }
   var lastname: String = lastname
       set(value) {
           field = value.toLowerCase().capitalize()
           updateCount++
       }
   var updateCount = 0
}

When setting either properties, the setter methods will be called recursively (resulting in a runtime error) because they attempt to write to the member, rather than the backing field.

To fix this change:

name = value.toLowerCase().capitalize() to field = value.toLowerCase().capitalize()

and

lastname = value.toLowerCase().capitalize() to field = value.toLowerCase().capitalize()