Main function Val and var Type inference Numeric types String templates Ranges Packages and imports Nullable types

If expression When expression For loops While loops Do while loops Break and continue Labeled returns Smart casts

Default arguments Named arguments Vararg parameters Expression body functions Local functions Higher-order functions Function references Inline functions

Primary constructors Secondary constructors Init blocks Data classes Enum classes Sealed classes Object declarations Companion objects

Open classes Overriding members Abstract classes Interfaces Delegation by Property delegation Visibility modifiers Nested and inner classes

List and MutableList Set and MutableSet Map and MutableMap Map transformation Filter transformation Fold reduction GroupBy Sequences

Safe call operator Elvis operator Not-null assertion Safe casts Generic classes Generic constraints Out variance In variance

Extension functions Extension properties Infix functions Operator overloading Scope function let Scope function apply Scope function run Type-safe builders

Suspend functions Launch coroutine Async and await CoroutineScope WithContext Flow basics StateFlow Coroutine cancellation

Java interoperability SAM conversions Annotations Reflection Use resource handling JUnit testing Gradle Kotlin DSL Serialization