GraphQL is a query language and runtime for APIs, developed by Facebook (Meta) in 2012 and open-sourced in 2015.It provides a flexible and efficient way for clients to request exactly the data they need — nothing more, nothing less. 🧩 Key Idea In GraphQL, the client defines the structure of the response.Unlike REST, where…
Here’s a clear and concise list of the main HTTP status codes grouped by category, along with what they mean 👇 🟢 1xx – Informational These indicate that the request was received and understood, and the server is continuing the process. CodeMeaningDescription100ContinueThe client should continue with its request.101Switching ProtocolsServer is switching protocols as requested.102ProcessingThe…
DDD stands for Domain-Driven Design. It’s a way of designing software by focusing on the business domain — the real-world problem the software is trying to solve — rather than just the technology. 🔹 Domain The domain is the business problem space — what your software is about.It’s the core logic and rules that…
BDD stands for Behavior-Driven Development — it’s an evolution of TDD (Test-Driven Development) that focuses on how the software should behave from the user’s point of view. Instead of writing tests in a technical way, BDD describes them in natural, human-readable language — usually using the Given–When–Then format. 💡 Simple Example Let’s say we’re…
TDD stands for Test-Driven Development — it’s a software development practice where you write tests before writing the actual code. Here’s how it works, step by step (often called the Red–Green–Refactor cycle): 🟥 Red – Write a test that defines a small piece of functionality you want. The test will fail at first because…
Creating a thread in Java can be done in a few different ways — all based on the java.lang.Thread class and the java.lang.Runnable interface. Here’s a clear breakdown 👇 🧩 1. By Extending the Thread Class You can create a thread by extending the Thread class and overriding its run() method. Example: class MyThread…
What is Polymorphism? Polymorphism means "many forms." In Java, it allows an object to take multiple forms. It is one of the four main OOP (Object-Oriented Programming) concepts, along with inheritance, encapsulation, and abstraction. Polymorphism in Java occurs in two main types: Compile-time Polymorphism (Method Overloading) Happens at compile time. Achieved by method overloading…
🔑 What are Access Modifiers? Access modifiers define the visibility or accessibility of classes, methods, and variables. They control who can access what in your program. Java has four main access modifiers: ModifierClassPackageSubclassWorld (anywhere)private✔✖✖✖default✔✔✖✖protected✔✔✔✖public✔✔✔✔ “Default” access is when no modifier is specified. 🔑 1. Private Accessible only within the same class. Used to encapsulate…
Operators are special symbols in Java that perform operations on variables and values. They are essential in expressions, calculations, comparisons, and logical decisions. Here’s a complete breakdown: 🔑 1. Arithmetic Operators Used for mathematical calculations. OperatorDescriptionExample+Addition5 + 3 = 8-Subtraction5 - 3 = 2*Multiplication5 * 3 = 15/Division10 / 2 = 5%Modulus (remainder)10 %…
The Object class in Java is one of the most fundamental concepts. Let’s break it down clearly. 🔑 What is the Object Class? Object is the root superclass of all classes in Java. Every class implicitly extends Object if it does not explicitly extend another class. It is part of the java.lang package. class…