
This course includes our updated coding exercises so you can practice your skills as you learn.
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Explore creational, structural, and behavioral design patterns from the Gang of Four to build scalable, extensible, and maintainable object-oriented software, improving low level design with hands-on examples.
Explore design patterns and solid principles through paired problems and refactored solutions, with GitHub codes, PDFs, exercises, tests, and quizzes for Java and data structures.
Learn how to design a Java payment service using classes, inheritance, and interfaces to model credit card, debit card, and UPI as interchangeable payment methods with runtime polymorphism.
Explore how access modifiers control visibility of data members and methods in Java, including private, protected, public, and default (package-private), with a debit card example and getter usage.
The single responsibility principle requires a class to have one reason to change, moving responsibilities to dedicated classes such as user repository, notification service, and invoice repository.
we explain the open closed principle, showing how software should be open for extension and closed for modification through abstraction and runtime polymorphism in a payment processor.
Learn how to apply the Liskov substitution principle to substitute a superclass with a subclass without breaking correctness, using readable and writable file interfaces.
Learn how the interface segregation principle splits large interfaces into smaller ones to improve maintainability, flexibility, and testability, using printer, scanner, and copier interfaces.
Explore how dependency inversion uses a notification channel interface to decouple high level from low level modules, enabling email, sms, or future whatsapp support.
Design patterns provide reusable solutions for how classes and objects communicate, boosting code reuse, maintainability, and scalability with patterns like factory, singleton, and observer from the Gang of Four.
Explore behavioral design patterns such as observer, strategy, command, template method, iterator, state pattern, mediator, and memento, and learn how objects communicate to achieve loose coupling.
Use the memento pattern to enable undo and redo by capturing the editor state in a memento. Manage history with a caretaker to restore state without exposing internal details.
The memento pattern uses an editor as originator, a memento to store its state, and a caretaker for history to enable undo and restore.
Learn how the observer pattern enables loose coupling between a weather station and multiple devices that display temperature updates, replacing hard wired notifications.
Learn how to implement the observer pattern with a weather station data source and multiple device observers, using a shared observer interface, notify, add/remove observer methods, and a publisher-subscriber pattern.
Implement the observer pattern with a weather station as the subject and display and mobile observers, showing attach, detach, notify, and runtime polymorphism via update methods.
Enable loose coupling by decoupling the subject from observers via an interface; the observer pattern supports open-closed principle and suits use cases like event listeners, stock monitoring, and news publishing.
Explore the strategy pattern by solving a payment system problem with multiple methods like credit card, PayPal, and UPI, avoiding if else conditions and open closed principle violations.
The strategy pattern encapsulates payment methods such as credit card, debit card, and UPI. The payment service delegates processing to these strategies at runtime, upholding open-closed and single-responsibility principles.
Examine how the command pattern decouples button UI from text editor actions, replacing hard-coded onClick with configurable commands to support multiple apps and a generalized framework.
Decouple editor actions from UI buttons by introducing a generic command interface and concrete commands. This enables undo, redo, and easy extension through button-driven command execution.
Apply the command pattern to decouple the invoker from the editor as the receiver, using a command interface, concrete commands, and support for undo, redo, and extensibility.
Discover the template method pattern, a behavioral design approach that centralizes open and close steps while varying the parsing logic for csv, json, and xml.
Unify code with template method pattern in an abstract data parser that opens and closes files, while CSV and JSON parsers implement parse and avoid duplication, following the dry principle.
Explain the iterator pattern as a common interface to traverse any collection—array, list, map, or set—so the client code stays decoupled from internal structures.
Learn how the iterator pattern enables uniform traversal across collections by implementing a nested book iterator with has next, encapsulated inside the book collection for data-structure agnosticism.
The iterator pattern offers a uniform traversal interface across collections, hides internal structure, enables separation of concerns, and supports forward and backward iterators.
Are you looking to take your Java programming skills to the next level and master the art of designing scalable, maintainable, and efficient software systems? In this course, Low Level System Design, Design Patterns & SOLID Principles, Prateek Narang, an experienced Software Engineer and Instructor and having worked with companies like Google, Scaler, Coding Minutes etc will guide you through the world of object-oriented design patterns, essential for building robust applications in real-world scenarios.
What You’ll Learn:
Understand the fundamental design patterns used in software engineering and how to apply them effectively in Java.
Explore creational, structural, and behavioral patterns, and their practical use cases.
Write cleaner, more efficient code by leveraging well-established design principles.
Learn how to improve low-level design for building scalable and maintainable applications.
Solve complex design problems with ease using proven design techniques.
Benefits of Doing a Design Patterns Course
Improved Software Design Skills:
Learn how to build flexible, maintainable, and scalable software systems by applying proven design solutions.
Design Patterns are tried-and-tested solutions that help you handle recurring problems in software design.
Enhances Problem-Solving:
Acquire a deeper understanding of common software design challenges and how to solve them using structured approaches.
Patterns provide frameworks for thinking about structural, creational, and behavioral issues in software.
Better Code Readability and Maintenance:
Patterns lead to code that is more understandable and self-explanatory.
By following widely known design patterns, your codebase becomes easier for other developers to read and maintain.
Code Reusability:
Design patterns encourage reusability, which reduces redundancy and makes your codebase more efficient and concise.
Patterns like Factory, Prototype, and Singleton encourage the creation of reusable objects and solutions.
Align with Industry Best Practices:
Design patterns are a fundamental part of object-oriented design and are widely adopted by the industry. Mastering them shows you’re following industry standards.
In interviews and workplace challenges, design patterns often serve as best practices when architecting solutions.
Better Team Collaboration:
Design patterns provide a shared vocabulary for discussing design problems and solutions with other developers.
This common language improves collaboration within teams and makes communication more effective.
Preparation for System Design Interviews:
Many technical interviews for mid-to-senior roles focus on system design questions where knowledge of design patterns is essential.
Mastering the foundational concepts of design patterns is crucial for successfully handling these interviews and presenting scalable, optimized solutions.
Handle Complex Systems:
Gain the ability to break down complex systems into smaller, manageable pieces using patterns like Composite, Facade, and Bridge.
Structural patterns allow you to design systems that are easier to extend and maintain.
Build Scalable and Extensible Architectures:
By using design patterns, you can create systems that can scale with increasing complexity and adapt to changing requirements.
Patterns like Decorator and Strategy support adding functionality or swapping algorithms without modifying existing code.
Improved Decision-Making:
By understanding the pros and cons of each design pattern, you'll be better equipped to make decisions about which approach suits a specific situation.
It enables you to evaluate different design options and pick the most optimal solution.
Framework and Library Understanding:
Modern frameworks and libraries heavily rely on design patterns (e.g., Singleton in Spring Framework, Factory in GUI toolkits).
A strong grasp of design patterns helps you better understand how these frameworks work under the hood.
Career Growth and Opportunities:
Mastery of design patterns is often expected for senior-level roles (e.g., architect, tech lead), improving your chances for career advancement.
It increases your confidence to tackle complex design problems and lead teams in making architectural decisions.
Design patterns are the foundation of good software design. They help you solve recurring problems and improve the structure and quality of your code. This course offers hands-on examples and real-world scenarios to help you understand and implement these patterns effectively.
Whether you’re preparing for technical interviews or aiming to write better software, this course will give you the practical skills and confidence you need to level up your design capabilities.