Java Backend Development · Raaha
Intensives
Java Backend Development Build tested, production-style services with Java 21 and Spring Boot.
Learn modern Java, SQL and Spring Boot by building real services. You'll handle transactions, security, testing with real databases and Docker, and finish with a documented backend you can defend.
Skills
17
15 required for the role
Total work
63h
at the reference pace
What you're aiming at
The role A junior backend developer builds and maintains APIs and data layers, writes tests, handles errors and security properly, and documents services for other developers.
Java Developer Intern Junior Backend Developer Associate Software Engineer Backend Apprentice
A credible portfolio in this field has
✓ Two GitHub repositories with CI and tests✓ OpenAPI documentation✓ Architecture decision records✓ An honest note on AI useSpecialisations
What you can focus on in phase 3 Transactional systems High-performance APIs Secure services
17 skills
The skill map Each one is verified by evidence, never by marking a lesson complete.
PHASE 1 · FOUNDATION
Java 21 foundations Object-oriented design Collections and generics Exceptions and file handling Unit testing
PHASE 2 · APPLICATION
SQL and PostgreSQL HTTP and REST Spring Boot Validation and error handling JPA and JDBC
The plan
What each phase asks of you PHASE 1 · WK 1–3
Foundation
Repair gaps, learn core concepts and tools, and produce small evidence.
16 tasks · 14.3h
Exercise Programming basics drills wk 1 · 1h Lesson Java 21 foundations wk 1 · 1h Exercise Command-line expense tracker wk 1 · 1.5h Lesson Object-oriented programming wk 1 · 50m Proof of ability
Projects What you'll have built and can show someone.
Hostel booking API
A tested REST API for booking hostel rooms without double-booking.
about 10 hours
Portfolio-grade Campus wallet with idempotent transfers
A wallet service where transfers are safe under retries and concurrency.
about 15 hours
Portfolio-grade Clinic scheduling backend
A secure, documented scheduling service with CI.
about 20 hours
Transactions Authentication and security Concurrency Caching and performance Docker
PHASE 4 · PROOF OF ABILITY
API documentation Integration testing
Violet marks skills an employer expects at entry level. States run Exposed → Practising → Demonstrated → Verified.
Reflection
Week 1 reflection
wk 1 · 20m
Exercise Model a library system wk 2 · 1.5h
Lesson Collections and generics wk 2 · 50m
Exercise Collections kata wk 2 · 1.3h
Exercise Stretch: a generic repository wk 2 · 45m
Reflection Week 2 reflection wk 2 · 20m
Exercise CSV importer with error handling wk 3 · 1.5h
Lesson Unit testing with JUnit 5 wk 3 · 50m
Exercise Test your importer wk 3 · 1.3h
Exercise Debugging drills wk 3 · 45m
Quiz Java foundations check wk 3 · 20m
Reflection Week 3 reflection wk 3 · 20m PHASE 2 · WK 4–6
Application
Mini-projects, practical exercises, peer review and applied assessments.
16 tasks · 14.1h
Lesson SQL and PostgreSQL wk 4 · 1h Exercise Design a hostel booking schema wk 4 · 1.3h Lesson HTTP and REST wk 4 · 45m Exercise Design the booking API wk 4 · 1h Peer review Review a squad member's work wk 4 · 30m Reflection Week 4 reflection wk 4 · 20m Exercise First REST API with Spring Boot wk 5 · 1.7h Exercise Validation and error handling wk 5 · 1.5h Mini-project Mini-project 1: tested REST API wk 5 · 1.3h Peer review Review a squad member's work wk 5 · 30m Reflection Week 5 reflection wk 5 · 20m Exercise Persist with JPA and PostgreSQL wk 6 · 2h Lesson JDBC, JPA and the N+1 problem wk 6 · 45m Quiz Web and data check wk 6 · 20m Peer review Review a squad member's work wk 6 · 30m Reflection Week 6 reflection wk 6 · 20m PHASE 3 · WK 7–9
Specialisation
Pick a focus area, work on real cases and build a larger project.
15 tasks · 17.8h
Lesson Transactions and consistency wk 7 · 50m Exercise Specialisation: idempotent money transfer wk 7 · 2.5h Exercise Specialisation: fast catalogue API wk 7 · 2.5h Exercise Specialisation: secure the API wk 7 · 2.5h Exercise Project 2 brief wk 7 · 45m Reflection Week 7 reflection wk 7 · 20m Lesson Authentication fundamentals wk 8 · 45m Exercise Concurrency fundamentals wk 8 · 1.5h Exercise Containerise your service wk 8 · 1.3h Peer review Review a squad member's work wk 8 · 30m Reflection Week 8 reflection wk 8 · 20m Milestone Mini-project 2: transactional service wk 9 · 2.5h Exercise Stretch: add caching wk 9 · 45m Peer review Review a squad member's work wk 9 · 30m Reflection Week 9 reflection wk 9 · 20m PHASE 4 · WK 10–11
Proof of Ability
A portfolio-grade project, documentation, review and revision.
10 tasks · 10.3h
Exercise Integration tests with Testcontainers wk 10 · 1.3h Milestone Final project: production-style backend wk 10 · 2.5h Portfolio README and API documentation draft wk 10 · 1.3h Peer review Review a squad member's work wk 10 · 30m Reflection Week 10 reflection wk 10 · 20m Revision Revise your final project wk 11 · 2h Defence Project defence wk 11 · 40m Portfolio Architecture decision record and final README wk 11 · 1h Peer review Review a squad member's work wk 11 · 30m Reflection Week 11 reflection wk 11 · 20m PHASE 5 · WK 12–13
Opportunity Readiness
Resume, portfolio, project defence and your next 30 days.
8 tasks · 6.4h
Career Resume for backend roles wk 12 · 1h Exercise Backend interview practice wk 12 · 1.3h Portfolio Finalise your portfolio profile wk 12 · 1h Reflection Week 12 reflection wk 12 · 20m Assessment Final evaluation: code review wk 13 · 1h Portfolio Final demo video wk 13 · 1h Career Your next 30 days wk 13 · 30m Reflection Week 13 reflection wk 13 · 20m