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

Like for more ❤️

Java Backend Development is a highly in-demand and well-paying job in the tech industry.

If you're looking to become an excellent Java Developer, here's a roadmap that includes various online resources:

1. Core Java

First comes the fundamentals of Java Programming, here you will understand OOP concepts, conditional statements, collection frameworks,and many more.

https://youtube.com/playlist?list=PLd3UqWTnYXOnjGmyjD3zbIkyLXP15-6w0&si=UYvQhVNlZQYCH1Il

2. JDBC

A  Java API that allows you to access tabular data, especially data stored in a relational database.

https://youtube.com/playlist?list=PLsyeobzWxl7rU7Jz3zDRpqB-EODzBbHOI&si=Cc45vpeRXGIUKbfn

3. SQL

Get a good understanding of SQL, which is necessary to work with JDBC to write queries.

https://youtu.be/7S_tz1z_5bA

4. JSP + Servlet

Learn JSP and Servlet, which are used for writing web pages for web applications and handling client requests on the server-side.

https://youtube.com/playlist?list=PLE0F6C1917A427E96&si=TQeOIgluG3R29622

5. Spring Framework

5.1. Core Spring Framework

https://youtu.be/GB8k2-Egfv0?si=dHYp6rFkGVl9RMt8

5.2. Spring REST & Spring DATA

https://youtu.be/GwYUjzPrQTM?si=hJfmpukii2WnofxQ

5.3. Spring Security
Spring Security is the primary choice for implementing application-level security

https://youtu.be/sm-8qfMWEV8?si=uMkpBxOUXIptZif9

6. Hibernate Framework

Hibernate is a Java framework that simplifies the development of Java application to interact with the database. It is an open source, lightweight, ORM (Object Relational Mapping) tool.

https://youtu.be/Yv2xctJxE-w?si=q4FIOBxxX-Y0Qj5q

7. Spring Boot

Spring Boot is the ultimate framework and Makes Java Web Development less boilerplate, it can help you make production-ready applications in no time.

https://youtu.be/msXL2oDexqw?si=XB19MCCECAggcB18

8. Basic DevOps

8.1. Learn to Use AWS & Deploy Java Apps

https://youtube.com/playlist?list=PLVz2XdJiJQxxurKT1Dqz6rmiMuZNdClqv&si=bJyg0Np11PkGDIKO

8.2. Learn Basic Docker:

https://youtu.be/p28piYY_wv8?si=Xoqje7MJad1NeE9g

8.3. Learn Basic Kubernetes:

https://youtu.be/rTNR7vDQDD8?si=dgzwxQof7yGHUP4n

8.4. Deploy Spring Boot App on Kubernetes:

https://youtu.be/EZolJ4lNiYc?si=Kw09qKwMp_LxHTvw

9. Basic of git and GitHub
https://youtu.be/apGV9Kg7ics?si=MHtCgD8o7XqpU4W3

10. Java Microservices

https://youtu.be/tuJqH3AV0e8?si=1jjrWl4l4uYGrE5i

14. Java Quick revision for Interviews

https://youtu.be/oYXivKMSEqM?si=tngbZrvgbAwsShEb

15. Spring JMS(java messaging services)

JMS is a standard Java API that allows a Java application to send messages to another application.

https://youtube.com/playlist?list=PLmCsXDGbJHdibOx6axScPiuHA8ftsrmut&si=J0qjBSbB4GDCeTOv

𝐉𝐨𝐢𝐧 𝐭𝐡𝐢𝐬 𝐭𝐞𝐥𝐞𝐠𝐫𝐚𝐦 𝐠𝐫𝐨𝐮𝐩 𝐟𝐨𝐫 𝐩𝐫𝐞𝐦𝐢𝐮𝐦 Resources/Notes: https://t.iss.one/udacityfreecourse