The Java roadmap

Every Java lesson we teach, laid out as one path. Each station is a stage; tap any lesson to open it. Stations turn teal as you finish them.

Legend:Lesson stageStage completeTap a lesson to open it

Foundations

JDK vs JRE vs JVM

Primitive Types & Variables

Control Flow (if/else, switch, loops)

Packages & Imports

Object-Oriented Programming

Classes & Objects

Inheritance & super

Interfaces & Abstract Classes

Polymorphism & Encapsulation

Collections & Generics

List & ArrayList / LinkedList

Set & HashSet / TreeSet

Map & HashMap / ConcurrentHashMap

Java Generics (<T>)

Streams & Functional Programming

Lambda Expressions (->)

The Stream API (map, filter, reduce)

Functional Interfaces

Handling Nulls with Optional

Modern Java & Concurrency

Records & Sealed Classes (Java 17+)

Multi-Threading Basics (Thread, Runnable)

Virtual Threads (Project Loom - Java 21)

Memory Management & Garbage Collection

Build Tools & Testing

Build Automation with Maven

Gradle Basics

Unit Testing with JUnit 5

Mocking with Mockito

Enterprise & Spring Boot

Spring Boot Overview

Dependency Injection (IoC Container)

Spring Data JPA & Hibernate

Building REST APIs (@RestController)