Monirul Islam’s Post

🧠 5 Things Junior Developers Should NOT Learn First Yes — not first. Because learning abstractions before fundamentals often creates developers who can talk about architecture… …but struggle to explain their own code. I’ve seen juniors explain: • Dependency Injection • Clean Architecture • Repository patterns • Design patterns • Generic base classes But then struggle with basic questions like: • Who creates this object? • What responsibility does this class have? • Why does this layer exist? That’s backwards. 1️⃣ Dependency Injection DI is powerful. But it hides important concepts: • object creation • ownership • lifetimes If you don’t understand those first, DI becomes magic from a template. And magic doesn’t build engineers. 2️⃣ Repository Pattern Everywhere You’ve probably seen something like: • IUserRepository • UserRepository • UserService • UserManager Four layers. One method call. Abstraction without duplication is just extra indirection. 3️⃣ Clean Architecture on Day One Multiple projects. Strict layers. Perfect folder structure. But no real domain complexity. Architecture should be a response to pain, not a starting point. 4️⃣ Generic Base Classes Examples: • BaseService<T> • BaseHandler<TRequest, TResponse> Abstraction should come after repetition, not before. Write real implementations first. 5️⃣ Design Patterns From Memory Strategy. Factory. Builder. If you cannot explain the problem they solve, they are just decorations. Patterns are vocabulary. But vocabulary without experience doesn’t create understanding. 💡 Important clarification I’m not saying juniors shouldn’t learn these. I’m saying they shouldn’t learn them first. Start with: ✔ clear responsibilities ✔ explicit object creation ✔ simple readable code ✔ understanding your own logic You don’t become a better engineer by stacking abstractions. You become better by understanding what those abstractions hide. 💬 Curious to hear other opinions: Should junior developers start with architecture and patterns, or should they master simplicity first? #dotnet #csharp #softwareengineering #backenddevelopment #cleanarchitecture #programming #developerlearning PC: Stefan Đokić

𝗢𝗻𝗲 𝘀𝗺𝗮𝗹𝗹 𝗵𝗮𝗯𝗶𝘁 𝘁𝗵𝗮𝘁 𝗱𝗿𝗮𝗺𝗮𝘁𝗶𝗰𝗮𝗹𝗹𝘆 𝗶𝗺𝗽𝗿𝗼𝘃𝗲𝗱 𝗺𝘆 𝗰𝗼𝗱𝗲 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 Early in my career, I used to write code like this: 𝘪𝘧(𝘶𝘴𝘦𝘳 != 𝘯𝘶𝘭𝘭){   𝘪𝘧(𝘶𝘴𝘦𝘳.𝘨𝘦𝘵𝘗𝘳𝘰𝘧𝘪𝘭𝘦() != 𝘯𝘶𝘭𝘭){     𝘪𝘧(𝘶𝘴𝘦𝘳.𝘨𝘦𝘵𝘗𝘳𝘰𝘧𝘪𝘭𝘦().𝘨𝘦𝘵𝘈𝘥𝘥𝘳𝘦𝘴𝘴() != 𝘯𝘶𝘭𝘭){       𝘤𝘪𝘵𝘺 = 𝘶𝘴𝘦𝘳.𝘨𝘦𝘵𝘗𝘳𝘰𝘧𝘪𝘭𝘦().𝘨𝘦𝘵𝘈𝘥𝘥𝘳𝘦𝘴𝘴().𝘨𝘦𝘵𝘊𝘪𝘵𝘺();     }   } } It works… but it’s 𝗺𝗲𝘀𝘀𝘆, 𝗵𝗮𝗿𝗱 𝘁𝗼 𝗿𝗲𝗮𝗱, 𝗮𝗻𝗱 𝗲𝗮𝘀𝘆 𝘁𝗼 𝗯𝗿𝗲𝗮𝗸. Later I learned a simple principle: 𝗥𝗲𝗱𝘂𝗰𝗲 𝗻𝗲𝘀𝘁𝗶𝗻𝗴. 𝗜𝗻𝗰𝗿𝗲𝗮𝘀𝗲 𝗰𝗹𝗮𝗿𝗶𝘁𝘆. Refactoring it using 𝘖𝘱𝘵𝘪𝘰𝘯𝘢𝘭 or guard clauses makes the code much cleaner: 𝘖𝘱𝘵𝘪𝘰𝘯𝘢𝘭.𝘰𝘧𝘕𝘶𝘭𝘭𝘢𝘣𝘭𝘦(𝘶𝘴𝘦𝘳)     .𝘮𝘢𝘱(𝘜𝘴𝘦𝘳::𝘨𝘦𝘵𝘗𝘳𝘰𝘧𝘪𝘭𝘦)     .𝘮𝘢𝘱(𝘗𝘳𝘰𝘧𝘪𝘭𝘦::𝘨𝘦𝘵𝘈𝘥𝘥𝘳𝘦𝘴𝘴)     .𝘮𝘢𝘱(𝘈𝘥𝘥𝘳𝘦𝘴𝘴::𝘨𝘦𝘵𝘊𝘪𝘵𝘺)     .𝘪𝘧𝘗𝘳𝘦𝘴𝘦𝘯𝘵(𝘤𝘪𝘵𝘺 -> 𝘱𝘳𝘰𝘤𝘦𝘴𝘴(𝘤𝘪𝘵𝘺)); Cleaner code isn’t just about aesthetics. It helps with: Better readability Fewer bugs Easier maintenance for your future self After 𝟳+ 𝘆𝗲𝗮𝗿𝘀 𝗼𝗳 𝗱𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁, I’ve realized: Good developers make code work. Great developers make code understandable. What small coding habit improved your code quality the most? #Java #CleanCode #SoftwareEngineering #BackendDevelopment #Programming #Developers

SOLID Principles —> A Must-Know for Every Developer Designing with OOP If you're designing software using Object-Oriented Programming, understanding SOLID principles is not optional — it's essential. Originally introduced by Robert C. Martin (Uncle Bob), SOLID principles help developers build systems that are: ✔ Maintainable ✔ Scalable ✔ Testable ✔ Flexible ✔ Easy to extend Whether you're building a Spring Boot backend, microservices architecture, or enterprise applications — SOLID is foundational. 🔹 What is SOLID? S — Single Responsibility Principle (SRP) A class should have only one reason to change. 👉 Separate business logic, persistence logic, and notification logic into different classes. O — Open/Closed Principle (OCP) Software entities should be open for extension but closed for modification. 👉 Instead of modifying existing code to add new features, extend it using interfaces and polymorphism. L — Liskov Substitution Principle (LSP) Subclasses should be replaceable with their parent class without breaking behavior. 👉 Proper inheritance ensures predictable systems. I — Interface Segregation Principle (ISP) Don’t force a class to implement methods it doesn’t use. 👉 Prefer small, focused interfaces over large generic ones. D — Dependency Inversion Principle (DIP) Depend on abstractions, not concrete implementations. 👉 Use interfaces and dependency injection to reduce tight coupling. 🔥 Real-World Example (Spring Boot) In an Order Management system: Business logic handled in OrderService (SRP) Payment methods implemented using Strategy pattern (OCP) Interfaces injected via Spring Dependency Injection (DIP) Separate small interfaces for user operations (ISP) Result? ✔ Loose coupling ✔ Easy unit testing ✔ Clean architecture ✔ Better scalability 💡 Why Every Developer Must Know SOLID When systems grow: Code becomes complex Changes introduce bugs Tight coupling slows development SOLID principles prevent this. They turn average code into production-ready architecture. 📌 If you're preparing for interviews, building enterprise apps, or working on scalable systems — mastering SOLID is mandatory. Clean code is not about writing less code. It's about writing code that survives growth. #Java #SpringBoot #SoftwareDesign #CleanCode #SOLIDPrinciples #BackendDevelopment

🧱 SOLID Principles – Clean Code Is Not Optional If your code is hard to extend, test, or scale… You’re probably violating SOLID. These 5 principles separate average devs from solid backend engineers 👇 🔹 S – Single Responsibility Principle A class should have only one reason to change. ❌ One class doing everything class InvoiceService { void calculateTotal() {} void saveToDB() {} void sendEmail() {} } ✅ Split responsibilities class InvoiceCalculator {} class InvoiceRepository {} class EmailService {} Pros • Cleaner structure • Easier testing • Better maintainability 🔹 O – Open/Closed Principle Open for extension, closed for modification. ❌ if-else based logic double discount(String type) { if(type.equals("NEW")) return 10; if(type.equals("PREMIUM")) return 20; return 0; } ✅ Strategy pattern interface DiscountStrategy { double apply(); } Pros • No modification of existing code • Easy to add new behavior • Cleaner design 🔹 L – Liskov Substitution Principle Child classes should not break parent behavior. class Bird { void fly() {} } class Penguin extends Bird { void fly() { throw new RuntimeException(); } } Rule If subclass changes expected behavior → redesign hierarchy. 🔹 I – Interface Segregation Principle Don’t force classes to implement unused methods. interface Worker { void work(); void eat(); } Better → Split into smaller interfaces. 🔹 D – Dependency Inversion Principle Depend on abstractions, not concrete classes. ❌ Tight coupling class OrderService { PaymentService payment = new PaymentService(); } ✅ Constructor injection class OrderService { private final PaymentService payment; OrderService(PaymentService payment) { this.payment = payment; } } Pros • Loose coupling • Easy mocking in tests • Scalable architecture 🧠 Rule of Thumb If adding a new feature forces you to edit existing classes → rethink your design. Clean architecture isn’t overengineering. It’s long-term speed. 👉 If you’re preparing for backend interviews, connect & follow – I share short, practical backend concepts regularly. #Java #SpringBoot #BackendDevelopment #CleanCode #SoftwareEngineering #JavaDeveloper #Microservices #SystemDesign #CodingInterview

Your code works. But does it scale? That's where Big-O Complexity separates juniors from seniors. Save this chart, it'll click faster than any textbook ever will. Writing code that works is level 1. Writing code that works for 1 million users is a completely different game. The difference lives in these 7 lines on a graph: 🟢 O(1) Instant. Dream tier. Hash table lookups. 🔵 O(log n) Barely breaks a sweat. Binary search. 🔵 O(n) Grows with input. Usually fine. 🟡 O(n log n) Merge sort territory. Still acceptable. 🟠 O(n²) Nested loops. Your server starts sweating. 🔴 O(2ⁿ) Naive Fibonacci. Pray your input stays small. 🔴 O(n!) Full panic mode. Do NOT ship this. Every interview asks about it. Every system design depends on it. Every senior engineer thinks in it. If you can look at code and feel the complexity, you're already ahead of 80% of developers. ♻️ Repost to help a dev level up before their next interview. P.s: Which one have you accidentally shipped into production? Comment below.

💡 SOLID Principles Every Developer Should Know Writing code that works is easy. Writing code that is clean, scalable, and maintainable is the real challenge. That’s where the SOLID Design Principles help. These 5 principles are the foundation of good Low Level Design (LLD) and are widely used in real-world software architecture. Let’s quickly look at them 👇 🔹 Single Responsibility Principle (SRP) A class should have only one reason to change. 📖 Read more: https://lnkd.in/gQUPDhz6 🔹 Open/Closed Principle (OCP) Software should be open for extension but closed for modification. 📖 Read more: https://lnkd.in/gCPFMRYy 🔹 Liskov Substitution Principle (LSP) Subclasses should be able to replace their parent classes without breaking behavior. 📖 Read more: https://lnkd.in/gU9B-4uE 🔹 Interface Segregation Principle (ISP) Clients should not be forced to depend on methods they don't use. 📖 Read more: https://lnkd.in/gGCcgavA 🔹 Dependency Inversion Principle (DIP) Depend on abstractions, not concrete implementations. 📖 Read more: https://lnkd.in/gtAdWXWQ ⚡ Mastering SOLID helps you write code that is: ✔ Easier to maintain ✔ Easier to extend ✔ Easier to test ✔ Production-ready I’m documenting Low Level Design concepts with examples here: 🌐 https://www.revisealgo.in If you're learning System Design or preparing for interviews, these concepts are essential. 💬 Which SOLID principle do you use the most in your projects? #systemdesign #softwareengineering #cleanarchitecture #lowleveldesign #coding #programming #SOLID #developers #backenddevelopment

Writing Better Code with SOLID Principles As developers, we often focus on making code work. But great engineers focus on making code maintainable, scalable, and easy to extend. One of the best guidelines for writing clean and maintainable code is the SOLID principles. Here’s a quick breakdown: 🔹 S — Single Responsibility Principle (SRP) A class or module should have only one reason to change. Each component should handle one responsibility only. 🔹 O — Open/Closed Principle (OCP) Software entities should be open for extension but closed for modification. Instead of changing existing code, extend it with new functionality. 🔹 L — Liskov Substitution Principle (LSP) Derived classes should be able to replace their base classes without breaking the application. 🔹 I — Interface Segregation Principle (ISP) Clients should not be forced to depend on interfaces they don't use. Better to create smaller, focused interfaces. 🔹 D — Dependency Inversion Principle (DIP) High-level modules should not depend on low-level modules. Both should depend on abstractions. When applied correctly, SOLID principles help us build systems that are: ✔ Easier to test ✔ Easier to maintain ✔ Easier to scale ✔ Less tightly coupled In modern backend frameworks like NestJS, these principles are naturally encouraged through dependency injection, modular architecture, and service layers. Clean architecture is not just about writing code — it's about designing systems that survive change. #SoftwareEngineering #CleanCode #SOLIDPrinciples #BackendDevelopment #NodeJS #NestJS #MERNStack #WebDevelopment

Most developers learn how to write code. But great developers learn how to design code. One of the most powerful foundations of clean and maintainable software design is SOLID Principles. These five principles help developers build systems that are easier to maintain, scale, and extend. S – Single Responsibility Principle A class should have only one reason to change. O – Open/Closed Principle Software entities should be open for extension but closed for modification. L – Liskov Substitution Principle Derived classes should be replaceable with their base classes without breaking functionality. I – Interface Segregation Principle Clients should not be forced to depend on interfaces they do not use. D – Dependency Inversion Principle Depend on abstractions, not on concrete implementations. Applying SOLID principles leads to: ✔ Cleaner architecture ✔ More maintainable code ✔ Easier testing ✔ Scalable applications As developers, writing working code is just the beginning — writing clean, extensible, and maintainable code is the real skill. #SOLIDPrinciples #CleanCode #SoftwareEngineering #DotNet #Programming #BackendDevelopment #SoftwareDeveloper

Recently, I came across a post describing the difference between a software developer and a software engineer, and it stuck with me A developer can take requirements and implement them in code. An engineer, on the other hand, helps define those requirements, thinks through the system end to end, and takes ownership from planning through production. The focus shifts from adding code to an existing system to deliberately shaping the system itself—minimizing technical debt, designing for clarity, and building something that can evolve. One skill I’ve always relied on is my ability to follow data flow. I like understanding where data originates, how it moves through an API, and where and why it changes along the way. I usually carry that mental map with me, which makes troubleshooting more efficient and often pushes me to refactor or rewrite parts of the system to improve structure rather than patch symptoms. Over time, that perspective has expanded. I’ve found myself thinking earlier in the process—identifying core entities and their attributes, considering how backend and frontend concerns align, and asking what needs to be true today so the application can scale tomorrow. Instead of focusing only on implementation, I now think about constraints, boundaries, and long-term maintainability. What’s been most interesting is realizing that this shift happened gradually. I often revisit modules I wrote in the past and rewrite them using cleaner abstractions or better patterns, sometimes wondering why I didn’t approach the problem that way initially. That reflection has been a learning process in itself. Today, I feel far more confident building new features and handling complex bugs. I’m comfortable rewriting modules when necessary, designing new components with future development in mind, and treating the system as a cohesive whole rather than a collection of features. My goal is no longer just to build software that works, but to engineer systems that are understandable, scalable, and ready for production from day one. This is the mindset I bring as a backend-focused software engineer at a mid-level: ownership from planning to production, strong data-flow intuition, and a constant bias toward improving system design, not just adding code. #python #develop #software #engineering #fastapi #async

💻 Stack Overflow vs Real Understanding: The Developer’s Dilemma Every developer has been here. You hit a bug. You search the error. You open Stack Overflow. You copy the solution. And suddenly… it works. 🎉 Problem solved… right? Not always. Copying code can fix the issue temporarily. But understanding the logic is what actually builds a strong developer. The internet gives answers. But real growth comes from asking: • Why does this solution work? • What problem is it solving internally? • How can I adapt it to my own codebase? Because sometimes copied code: ⚠ Works in development ⚠ Breaks in production ⚠ Creates hidden technical debt A simple rule many experienced engineers follow: ✅ Use online solutions as references, not shortcuts ✅ Break down the logic before implementing it ✅ Modify the solution to fit your system Great developers don’t just copy code. They study it, understand it, improve it, and make it their own. 🚀 If you're a developer, be honest: Have you ever fixed a bug with a solution you didn’t fully understand? 😅 #developers #programming #softwareengineering #coding #webdevelopment #techlearning