List of topics you need to cover if you're preparing for Java Interviews based on current Job market:

1. Core Java Fundamentals (Refer to already posted topics)
2. Advanced Java
- Design Patterns
- Multithreading
- Java Memory Model
- Performance Optimization
- Reflection & Dynamic Proxies
3. Spring Framework
- Spring core concepts
- Spring boot
- Spring Data JPA
- Spring Security
- Spring cloud
- Spring webflux
4. Hibernate
5. Testing (JUnit, Mockito, Integration, Functional, Performance Testing)
6. Build Tools (Maven / Gradle)
7. Logging
8. RDBMS, NoSQL DBs
9. WebSecurity Concepts
10. REST API concepts
11. CI/CD (Jenkins, GitHub Actions)
12. Containerization (Docker, Kubernetes)
13. Version Control (GitHub)
14. Monitoring (Grafana, ELK Stack etc)
15. Cloud (AWS, Azure, GCP (Very rare) )
16. Spring boot microservices
16. Messaging systems
17. Caching Strategies
18. System Design
19. Data Structures
20. Algorithms
21. Agile Methodologies
22. Behavioral questions

Learning DSA wasn’t just about acing interviews, --- it was about thinking better, building faster, and debugging smarter.

🎯 𝗛𝗲𝗿𝗲 𝗮𝗿𝗲 𝘁𝗵𝗲 𝟵 𝗰𝗼𝗿𝗲 𝗽𝗮𝘁𝘁𝗲𝗿𝗻𝘀 𝘁𝗵𝗮𝘁 𝘁𝗿𝗮𝗻𝘀𝗳𝗼𝗿𝗺𝗲𝗱 𝗵𝗼𝘄 𝗜 𝘀𝗼𝗹𝘃𝗲 𝗽𝗿𝗼𝗯𝗹𝗲𝗺𝘀:
• Sliding Windows
• Two Pointers
• Stack Based Patterns
• Dynamic Programing
• BFS/DFS (Trees & Graphs)
• Merge Intervals
• Backtracking & Subsets
• top-k Elements (Heaps)
• Greedy Techniques


🛤️ 𝗠𝘆 𝗣𝗮𝘁𝗵 𝘁𝗼 𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝗗𝗦𝗔:
• Started with basic problems on arrays & strings
• Solved 1-2 problems a day, consistently for 3 months
• Focused more on patterns than individual questions
• Made my own notes, revisited problems I struggled with
• Used visual tools to understand recursion & DP
• Practiced explaining my solutions out loud (like system design reviews)
• Applied patterns in real-world projects (DevOps automation, log parsing, infra tools)


💡 𝗟𝗼𝗼𝗸𝗶𝗻𝗴 𝗯𝗮𝗰𝗸, 𝗼𝗻𝗲 𝘁𝗵𝗶𝗻𝗴 𝗶𝘀 𝗰𝗹𝗲𝗮𝗿:
> It's not how many problems you solve, it's how well you can recognize the pattern hiding in each one.

You can find more free resources on my WhatsApp channel: https://whatsapp.com/channel/0029VahiFZQ4o7qN54LTzB17

2 Month Roadmap to learn Java and Spring from basics to advanced

Week 1-2: Core Java

- Basic Syntax: Data types, operators, loops (for, while, do-while)
- OOP Concepts: Classes, objects, inheritance, polymorphism, encapsulation, abstraction
- Collections Framework: List, Set, Map, Queue, Iterator, etc.
- Exception Handling: Try-catch, custom exceptions, multi-catch
- File I/O: Reading/writing files using java.io and java.nio
- Java 8+ Features: Lambdas, Streams, Optional, Functional Interfaces
- Multithreading: Threads, Runnable, ExecutorService, Future, and basic synchronization

Week 3-4: Advanced Java & JDBC

- JVM Internals: ClassLoader, JIT, memory management, garbage collection
- Generics: Usage and wildcards
- Design Patterns: Singleton, Factory, Strategy, Observer, Dependency Injection (Intro)
- JDBC: Connecting with databases (CRUD operations), PreparedStatement, Connection pooling

Week 5-6: Spring Framework (Basics)

- Spring Core
- Dependency Injection (DI) and Inversion of Control (IoC)
- Beans, Scopes, and Bean Life Cycle
- Autowiring and Spring Annotations
- Spring AOP: Aspect-Oriented Programming fundamentals
- Spring Data JPA: Basic CRUD operations with JPA
- Entities, Repositories, and Custom Queries

Week 7: Spring Boot (Basics)

- Spring Boot Fundamentals: Understanding the Spring Boot architecture
- REST API creation
- Spring Boot Annotations (@RestController, @RequestMapping, etc.)
- Running a Spring Boot application
- Spring Boot Auto Configuration: Application properties and profiles
- Spring Boot with Database: Integrate Spring Boot with MySQL using Spring Data JPA

Week 8: Spring Boot (Advanced)

- Security: Introduction to Spring Security (Basic Authentication)
- Advanced Spring Boot Features: Exception handling (@ControllerAdvice)
- Logging with Spring Boot
- Pagination and Sorting
- Testing: Write unit tests using JUnit and Mockito in Spring Boot

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