Constructors are a fundamental concept in Java, used to initialize objects. When you create an instance of a class, a constructor is automatically called. This special method sets the initial state of the object, assigning values to its fields and preparing it for use. Unlike regular methods, constructors don’t have a return type, not even […]
Polymorphism and Extensibility are two key principles of Object-Oriented Programming (OOP) in Java that allow for more flexible, scalable, and maintainable code. Let’s break down these concepts to understand how they work and why they’re essential for developers. What is Polymorphism? Polymorphism comes from the Greek words “poly” (many) and “morph” (forms). In Java, it
Java Inheritance is a core concept of Object-Oriented Programming (OOP) that allows a class (child) to acquire the properties and behaviors (methods) of another class (parent). This makes the code more reusable, organized, and easy to maintain. When you define a new class in Java, you can make it inherit from an existing class to
What is a Java HashMap? A HashMap in Java is a data structure that stores data in the form of key-value pairs. This means that each piece of data (a value) is associated with a unique identifier (a key). For example, imagine you have a list of student names and their corresponding grades. The names
Java ArrayLists are one of the most flexible and commonly used data structures. They allow you to store elements dynamically, meaning you can add or remove elements without worrying about the initial size of the list. This makes them much more versatile compared to traditional arrays, which have a fixed size. What is an ArrayList?