Learning Path
A structured roadmap for Java backend engineers targeting FAANG-level roles. Follow the phases sequentially — each builds on the previous.
Roadmap Overview
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flowchart TD
P1["🟢 Phase 1 — Foundations\nJava · OOP · Collections · JVM"]
P2["🟡 Phase 2 — Core Engineering\nSpring Boot · SQL · Threading · Testing"]
P3["🔴 Phase 3 — Distributed Systems\nMicroservices · Kafka · System Design · DevOps"]
P4["🟣 Phase 4 — Interview Ready\nDSA 200 Problems · Mocks · Behavioral"]
P1 -->|"Months 1-2"| P2 -->|"Months 3-4"| P3 -->|"Months 5-6"| P4
style P1 fill:#d1fae5,stroke:#059669,color:#000
style P2 fill:#fef3c7,stroke:#d97706,color:#000
style P3 fill:#fee2e2,stroke:#dc2626,color:#000
style P4 fill:#FFF8E1,stroke:#F9A825,color:#000Difficulty Legend
- Green — Foundations (start here, 2 months)
- Yellow — Core engineering skills (2 months)
- Red — Distributed systems & architecture (2 months)
- Purple — Interview-specific preparation (2 months)
Phase 1: Java Foundations
| Week | Topic | What to Master | Practice |
|---|---|---|---|
| 1 | Java Basics | Primitives, operators, control flow, methods | Write 10 small programs |
| 2 | OOP | Classes, inheritance, polymorphism, interfaces, abstract | Model 3 real-world systems |
| 3 | Collections | ArrayList, HashMap, TreeMap, HashSet, LinkedList | Implement a custom HashMap |
| 4 | Generics & Streams | Type parameters, wildcards, Stream API, lambdas | Refactor loops to streams |
| 5 | Exception Handling | Checked vs unchecked, try-with-resources, custom exceptions | Build error handling strategy |
| 6 | I/O & NIO | File operations, BufferedReader, Path, Files, channels | Build a log file parser |
| 7-8 | JVM & GC | Memory model, class loading, G1/ZGC, JIT compilation | Profile a sample app with VisualVM |
Milestone: Build a CLI application that reads CSV files, processes data using streams, and outputs results — handling all edge cases gracefully.
Phase 2: Core Engineering
| Week | Topic | What to Master | Practice |
|---|---|---|---|
| 9 | SOLID Principles | SRP, OCP, LSP, ISP, DIP with real examples | Refactor a messy codebase |
| 10 | Design Patterns | Factory, Strategy, Observer, Builder, Decorator | Implement each in a mini-project |
| 11 | Multithreading | Thread lifecycle, synchronized, volatile, happens-before | Build a producer-consumer system |
| 12 | Concurrency | ExecutorService, CompletableFuture, ConcurrentHashMap, locks | Build a parallel web crawler |
| 13-14 | Spring Boot | IoC/DI, annotations, REST controllers, JPA, profiles | Build a complete CRUD API |
| 15 | Database | Normalization, indexes, joins, transactions, query optimization | Design schema for e-commerce |
| 16 | Testing | JUnit 5, Mockito, integration tests, Testcontainers | Achieve 80%+ coverage on your API |
Milestone: Build a Spring Boot REST API with JPA, proper layered architecture, comprehensive tests, and Docker deployment.
Phase 3: Distributed Systems
| Week | Topic | What to Master | Practice |
|---|---|---|---|
| 17-18 | Microservices | Service decomposition, API gateway, service discovery | Split monolith into 3 services |
| 19 | Kafka | Producers, consumers, partitioning, exactly-once semantics | Build event-driven pipeline |
| 20 | Resilience | Circuit breakers, retries, bulkheads, rate limiting | Add resilience to your services |
| 21-22 | System Design | CAP, consistent hashing, sharding, replication | Design 2 systems per week |
| 23 | Docker & K8s | Containers, pods, services, deployments, config maps | Containerize and deploy your app |
| 24 | CI/CD & Cloud | GitHub Actions, AWS (EC2, RDS, S3, SQS, Lambda) | Set up full pipeline |
Milestone: Deploy a 3-service microservices system with Kafka, Docker Compose, monitoring (Prometheus + Grafana), and a CI/CD pipeline.
Phase 4: Interview Preparation
| Week | Focus | Daily Target |
|---|---|---|
| 25-26 | DSA: Arrays, Strings, HashMaps, Two Pointers | 3 problems/day |
| 27-28 | DSA: Trees, Graphs, BFS/DFS | 2-3 problems/day |
| 29-30 | DSA: DP, Backtracking, Greedy | 2 problems/day |
| 31 | System Design deep practice | 1 full design/day |
| 32 | Mock interviews + behavioral | 1 mock + review/day |
Milestone: Solve 150+ LeetCode problems across all patterns, design 15 systems end-to-end, and complete 5 mock interviews.
Recommended Resources
Books (Priority Order)
| Book | Why It Matters | When to Read |
|---|---|---|
| Effective Java (Bloch) | Java best practices, idiomatic code | Phase 1-2 |
| Clean Code (Martin) | Writing maintainable code | Phase 2 |
| Java Concurrency in Practice (Goetz) | Deep concurrency understanding | Phase 2 |
| Designing Data-Intensive Applications (Kleppmann) | Distributed systems fundamentals | Phase 3 |
| System Design Interview (Alex Xu) | Structured approach to design problems | Phase 3-4 |
| Cracking the Coding Interview (McDowell) | DSA patterns and behavioral prep | Phase 4 |
Online Platforms
| Platform | Best For |
|---|---|
| LeetCode | DSA practice (sort by company/frequency) |
| NeetCode | Curated problem lists with video explanations |
| System Design Primer | System design concepts and examples |
| ByteByteGo | Visual system design explanations |
| Baeldung | Java and Spring Boot tutorials |
| Spring Guides | Official Spring Boot guides |
| Visualgo | Algorithm visualization |
Video Resources
| Channel | Focus |
|---|---|
| Java Brains | Spring Boot, microservices |
| Tech Dummies (Gaurav Sen) | System design |
| Abdul Bari | Algorithms |
| NeetCode | DSA problem walkthroughs |
| Hussein Nasser | Backend engineering, protocols |
Study Principles
Consistency Over Intensity
2 hours daily for 8 months beats 10 hours on weekends. Build the habit first, then increase intensity.
Build Projects at Every Stage
Theory without practice doesn't stick. Each phase should produce a working project you can show in interviews.
Teach to Learn
Explain concepts to a rubber duck, a blog post, or a colleague. If you can't explain it simply, you don't understand it deeply enough.
Track Your Progress
Maintain a spreadsheet of problems solved, systems designed, and concepts mastered. Review weak areas weekly.
Weekly Schedule Template
| Day | Focus (2-3 hours) |
|---|---|
| Monday | DSA problems (current phase topic) |
| Tuesday | Theory (read book chapter or watch lecture) |
| Wednesday | DSA problems + review yesterday's theory |
| Thursday | Project work (build something with current concepts) |
| Friday | DSA problems (mix of new + revisit hard ones) |
| Saturday | System design OR mock interview |
| Sunday | Review week's progress, plan next week |