8A property cannot be initialized in the constructor. When do you reach for lateinit and when for by lazy?Easy
13A profile screen renders User(name=Alice).name instead of the name — what did the string template do?Easy
14Your for (i in 0..items.size) loop crashes on the last iteration — how do Kotlin's range operators differ?Easy
15list.first() crashed with NoSuchElementException on an empty response — which stdlib naming rule did you miss?Easy
16You add force: Boolean = false to a widely-called function — what changes for subclasses, Java callers and already-compiled modules?Medium
17You wrote return inside items.forEach { } to skip one item and the whole function stopped running — why?Medium
18Why does val id: String = raw ?: throw IllegalStateException() type-check when throw produces no value at all?Medium
19Two Array<String> values with identical contents compare as unequal and a data class holding one has broken equality — why?Medium
20if (user.isPremium) stops compiling once the JSON field arrives as Boolean? — which fix quietly turns "unknown" into "no"?Medium