Introduction Maps in Kotlin are collections of key-value pairs where each key is unique, and each key maps to exactly one value. Maps are useful for storing data that can be quickly retrieved using a key. Kotlin provides two types of maps: Map for immutable maps. MutableMap for mutable maps. This chapter will cover how …
Introduction Sets in Kotlin are unordered collections of unique elements. Unlike lists, sets do not allow duplicate elements. Kotlin provides two types of sets: Set for immutable sets and MutableSet for mutable sets. This chapter will cover how to create and manipulate both immutable and mutable sets, along with common operations that can be performed …
Introduction Lists in Kotlin are ordered collections of elements that can contain duplicates. Kotlin provides two types of lists: List for immutable lists and MutableList for mutable lists. Lists are commonly used for storing and manipulating collections of related data. This chapter will cover how to create and manipulate both immutable and mutable lists, along …
Introduction Collections in Kotlin are used to store groups of related objects. Kotlin provides a variety of collection types, such as lists, sets, and maps, that can hold multiple items. These collections come in two variants: mutable and immutable. Immutable collections cannot be modified after they are created, while mutable collections can be. This chapter …
Introduction Generics in Kotlin allow you to create classes, interfaces, and functions that can operate on any data type while maintaining type safety. Generics enable you to write more flexible and reusable code. This chapter will cover the basics of generics, including how to define generic classes and functions, use generic constraints, and understand variance. …
Introduction Null safety is a key feature in Kotlin designed to eliminate the danger of null references, commonly known as the "billion-dollar mistake". Kotlin provides several mechanisms to handle nullability in a safe and concise way. This chapter will cover the syntax and usage of nullable types, the safe call operator, the Elvis operator, and …
Introduction Custom exceptions in Kotlin allow you to define your own error types that are specific to your application’s requirements. By creating custom exceptions, you can provide more meaningful error messages and handle specific error conditions more gracefully. Custom exceptions are created by extending the Exception class or any of its subclasses. Creating Custom Exceptions …
Introduction The throw keyword in Kotlin is used to explicitly throw an exception. Throwing an exception disrupts the normal flow of the program, and it can be caught and handled using try-catch blocks. This chapter will cover how to use the throw keyword to throw exceptions, create custom exceptions, and handle them properly. Throwing Exceptions …
Introduction The finally block in Kotlin is used in conjunction with try and catch blocks to execute code regardless of whether an exception is thrown or not. The finally block is useful for releasing resources, closing connections, or performing any cleanup operations that need to be executed after a try-catch block. Using the finally Block …
Introduction Exception handling in Kotlin is essential for writing robust applications. The try-catch block is used to handle exceptions, ensuring that the program continues running even when an error occurs. Basic Try-Catch Syntax The try block contains code that might throw an exception, and the catch block handles the exception. Syntax try { // Code …
Introduction Exception handling is a mechanism to handle runtime errors, ensuring that the normal flow of the program is not disrupted. Kotlin provides a robust mechanism for handling exceptions using try, catch, finally, and throw keywords. This chapter will cover the syntax and usage of these keywords with examples. Basics of Exception Handling Syntax try …
Introduction Polymorphism is a core concept in object-oriented programming (OOP) that allows objects of different classes to be treated as objects of a common superclass. It enables a single interface to be used for a general class of actions, allowing for code that is more flexible and reusable. Polymorphism can be achieved through inheritance, interfaces, …
Introduction Abstraction is a fundamental concept in object-oriented programming (OOP) that allows you to define a blueprint for a class without providing a complete implementation. In Kotlin, abstraction is achieved using abstract classes and interfaces. Abstract classes can have abstract methods that do not have a body and must be implemented by subclasses. Interfaces can …
Introduction Sealed classes in Kotlin are a special type of class that allow you to represent restricted class hierarchies. When a value can have one of a limited set of types, you can use a sealed class to define it. Unlike regular classes, all subclasses of a sealed class are known at compile time, which …
Introduction Data classes in Kotlin are a special kind of class designed to hold data. They provide a concise syntax for defining classes whose primary purpose is to store values. Data classes automatically provide methods like equals(), hashCode(), toString(), copy(), and component functions. This makes them very convenient for working with immutable data. Defining a …
Introduction Abstract classes and methods are fundamental concepts in object-oriented programming (OOP). An abstract class cannot be instantiated and may contain abstract methods that must be implemented by subclasses. Abstract methods are defined without a body and must be overridden in the subclasses. This chapter will cover the syntax and usage of abstract classes and …
Introduction Interfaces in Kotlin define a contract that classes can implement. They can contain abstract methods as well as method implementations. Unlike classes, interfaces cannot store state, and a class can implement multiple interfaces, which helps in achieving multiple inheritances. Defining an Interface To define an interface in Kotlin, use the interface keyword. Interfaces can …
Introduction Inheritance is a fundamental concept in object-oriented programming (OOP) that allows a class to inherit properties and methods from another class. The class that inherits is called the subclass (or derived class), and the class being inherited from is called the superclass (or base class). In Kotlin, inheritance allows for code reuse and the …
Introduction Encapsulation is a fundamental concept in object-oriented programming (OOP) that restricts direct access to an object’s internal state and allows modification only through well-defined methods. This helps to protect the integrity of the object’s data and makes the code more modular and maintainable. In Kotlin, encapsulation is achieved using classes, visibility modifiers, and properties …
Introduction Visibility modifiers in Kotlin are used to control the visibility and accessibility of classes, objects, interfaces, constructors, functions, properties, and their setters. Kotlin provides four visibility modifiers: public, private, protected, and internal. This chapter will cover the syntax and usage of these visibility modifiers with examples. Visibility Modifiers 1. public The public modifier is …
Introduction Constructors are special functions used to initialize objects in Kotlin. They are called when an instance of a class is created. Kotlin supports two types of constructors: primary and secondary. This chapter will cover both types of constructors, including their syntax, usage, and examples. Primary Constructor The primary constructor is part of the class …
Introduction Classes and objects are fundamental concepts in object-oriented programming (OOP). A class defines a blueprint for an object, and an object is an instance of a class. This chapter will cover the basics of creating classes and objects in Kotlin, along with properties, methods, constructors, and initializer blocks. Defining a Class A class in …
Introduction Object-Oriented Programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and methods. Kotlin is a modern, statically typed programming language that supports OOP principles such as classes, objects, inheritance, polymorphism, and encapsulation. This chapter will cover the basics of OOP in Kotlin with examples. 1. Classes and …
Introduction Kotlin provides a rich set of built-in functions to manipulate strings effectively. These functions allow you to perform common tasks such as searching, replacing, formatting, and splitting strings. This chapter will cover the most commonly used string functions in Kotlin with examples. 1. length The length property returns the number of characters in a …
Introduction String templates in Kotlin provide a way to embed expressions within string literals, making string manipulation more concise and readable. String templates allow for the direct inclusion of variables and expressions inside strings, eliminating the need for concatenation operators. This chapter will cover the syntax and usage of string templates in Kotlin with examples. …