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In Kotlin, the idiomatic way to implement the Singleton pattern is to use an object declaration. object AppConfig { val appName = "MyApp" fun printConfig() { println("App name: $appName") } } You use it directly by its name: fun main() { AppConfig.printConfig() println(AppConfig.appName) } Kotlin guarantees that an object declaration: has exactly one instance is […]
You can mix OOP and functional programming in Kotlin by using objects/classes to model state, identity, boundaries, and domain concepts, while using functions/lambdas to model behavior, transformation, policies, and workflows. Kotlin is especially good at this because it supports: Classes, interfaces, inheritance, encapsulation Data classes and sealed classes Lambdas and higher-order functions Immutability with val […]
In Kotlin, type aliases let you give a shorter, more meaningful name to an existing type. They are especially useful when your code has deeply nested generics, function types, or repeated complex class structures. A type alias does not create a new type. It only creates an alternative name for an existing type. Basic syntax […]
In Kotlin, this, super, and @ labels are used to disambiguate which receiver or superclass member you mean, especially in nested scopes, inheritance, and inner classes. 1. this: refer to the current receiver Inside a class, this refers to the current instance of that class. class User(val name: String) { fun printName() { println(this.name) } […]
In Kotlin, the by keyword is used for delegation. It lets one object delegate behavior to another object instead of implementing everything manually. There are two common forms: Interface/class delegation Property delegation 1. Interface delegation If a class implements an interface, it can delegate the implementation of that interface to another object using by. Example […]
In Kotlin, properties can have custom getters and setters by defining get() and/or set(value) directly under the property. var propertyName: Type = initialValue get() { return field } set(value) { field = value } field is the backing field automatically generated by Kotlin when needed. Custom getter class Person( val firstName: String, val lastName: String […]
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