skill-based roadmap · Languages
Java Roadmap
A structured path from Java fundamentals to production-ready development, covering core language features, OOP, data structures, frameworks, and modern tooling employers expect.
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1. Stage 1: Java Foundations
JDK Setup & First Program
Establishes your local environment to write and run Java
Variables, Data Types & Operators
Core building blocks every Java program depends on
Control Flow: if, switch, loops
Enables programs to make decisions and repeat logic
Methods & Scope
Organises reusable logic and manages variable visibility
2. Stage 2: Object-Oriented Programming
Classes, Objects & Constructors
OOP is the central paradigm of every Java codebase
Inheritance & Polymorphism
Enables code reuse and flexible, extensible designs
Interfaces & Abstract Classes
Defines contracts that decouple implementation from behaviour
Encapsulation & Access Modifiers
Protects internal state and enforces clean API boundaries
3. Stage 3: Core Java APIs & Data Structures
Java Collections Framework
Lists, maps, and sets are used in nearly every application
Generics
Provides type-safe, reusable containers and methods
Exception Handling
Robust error handling is required in all production code
String Manipulation & StringBuilder
Text processing is a constant requirement across all domains
Java I/O & NIO
Reading and writing files is foundational for real applications
4. Stage 4: Modern Java & Functional Style
Lambdas & Functional Interfaces
Modern Java code relies heavily on concise functional expressions
Stream API
Enables declarative, pipeline-style data processing
Optional
Eliminates NullPointerException through explicit absence handling
Concurrency & Multithreading
Backend services require safe parallel execution understanding
5. Stage 5: Build Tools, Testing & Clean Code
Maven & Gradle
Dependency management and builds are industry standard skills
Unit Testing with JUnit 5
Automated tests are required in every professional Java project
Mockito for Mocking
Isolates units under test from external dependencies
SOLID Principles & Clean Code
Maintainable codebases require disciplined design principles
6. Stage 6: Spring Boot & Backend Development
Spring Core & Dependency Injection
Spring is the dominant Java enterprise framework worldwide
Spring Boot REST APIs
Building HTTP APIs is the core skill for backend Java roles
Spring Data JPA & Databases
Persisting data with an ORM is required in most backend work
Spring Security Basics
Authentication and authorisation are non-negotiable in production
7. Stage 7: Production Readiness & Job Prep
Docker & Containerisation for Java
Containerised deployments are the modern production standard
SQL & Database Design
Every backend role requires relational database competence
Git & GitHub Workflow
Version control and collaboration are required on every team
Data Structures & Algorithms for Interviews
Technical interviews test problem-solving with core CS concepts