Here's how you can ace discussing software architecture and design patterns in an interview.

It is always beneficial to support your answers with the examples. You may state 6-8 design patterns but it would make more sense if you convey the details of the use case in your project, the pain points encountered and the reasons of using these best practices targeting what pain points. There might be some design patterns preferred over others in your project. Feel free to share those as well, it highlights your knowledge on the topic in additional to your understanding of the business requirements and making appropriate decisions catering the same.

Real-life and/or project examples, use cases always helps to build the confidence in Interview. It not only illustrates actual use but also exemplifies it's understanding in depth. I would also recommend discussing why a specific design pattern outweighs other design patterns, or what are challenges with other design patterns considering the specific situation. During an interview nobody is interested to know the definitions of design patterns especially when it's beyond a certain experience level, whereas the above pointers help to demonstrate your potential and grip over the fundamentals.

Adapter pattern to maintain backward compatibility between eg java 7 to java 8 versions. Factory pattern - a connection pool which can connect to different databases (sql or nosql) from same factory call. Even if not used singleton. Explain how it works eg only 1 instance of angular service/java object exists. Next step into details, such as using private constructor in java and using a decorator in angular or using guards or preventing imports. And crucial to mention some of isues + cures before interviewer pick it up. Eg multi-threaded case(add synchronized) Decorator pattern or created a higher order function(similar to decorator). Re-compiled source of library of unit test + added custom decorator. Event driven vs microservice diff.

When explaining the benefits of design patterns in an interview, it's essential to demonstrate your understanding of software design principles and your ability to write maintainable, scalable, and efficient code. Sharing a few key points to highlight: 1. Improved Code Readability and Maintainability 2. Reduced Code Duplication 3. Easier Code Extension and Modification 4. Faster Development and Improved Productivity 5. Enhanced Collaboration and Communication 6. Better Problem-Solving and Decision-Making

Once, I implemented the Adapter Pattern in a new Java/Quarkus microservice to integrate with a legacy application, and I noticed several key benefits: - Code Reuse: It integrates existing classes without modification, reducing duplication. - Legacy Integration: Bridges legacy systems or third-party libraries without heavy refactoring. - Flexibility: Decouples the client from the interface, allowing easier changes. - Maintainability: Isolates implementation details, making updates simpler. - Testing: Supports mock adapters, simplifying unit testing. So this pattern ensures compatibility, flexibility, and clean, maintainable code.

For a multi-layered software will have multiple possibilities at each layers. Trade-offs are the variances your choices will introduce into the design. Also a good idea to have an estimate of cost of the choice. Always clarify. Non-functional or system design may involve asking yourself about scaling. And then presenting the choices of vertical vs horizontal scaling. Or possibly using load balancer. Checking some of the metadata of the systems eg how much queries system will receive of number or users. Whether database needs to be shard'ed. Should we send updates as single ones or batch. Explaining if events need to be recorded in message queues whether it's an event driven or micro-service architecture

Trade offs often arise due to availability of options/ alternatives to deal with one specific situation. One has to choose an option which is the right fit for not only technical design but also covering functional aspects at its best. Few examples while doing trade off, is the selected design/ solution - Cost optimized? - Performance optimized? - Scalable? - Maintainable? As rightly said "Every coin has 2 sides", whatever solution we choose we may end with a few drawbacks/ side effects of that implementation. However, we need to make trade off/ choose a solution what's best fit for business, and many times have to ignore pointers i.e. Complexity.

Based on various AI searches, these are the currently most discussed patterns: Singleton: Ensures a class has only one instance. Factory: Abstracts object creation, common in frameworks. Adapter: Integrates legacy systems or services with modern apps. Builder: Constructs complex objects step by step, improving flexibility. Observer: Essential in event-driven and reactive programming. Strategy: Interchangeable algorithms, used in dynamic systems. Decorator: Extends object functionality dynamically. CQRS: Separates read/write operations for scalability. Event Sourcing: Preserves state change history. Microservice Patterns: Circuit Breaker, API Gateway, Service Registry.