All Java courses

720 lessons across 28 courses · free to read

Reading copies of every lesson. The interactive versions — with visual explainers, labs and a Run button — live in the learning hub.

Core Java42 lessons · The Java language itself: types, loops, records, enums, exceptions… OOP43 lessons · Objects, inheritance, interfaces, records and the patterns that hold… Collections42 lessons · Lists, sets, maps and queues — how they work and which one to reach… Streams42 lessons · Turn loops into readable pipelines: filter, map, collect, and… Multithreading38 lessons · Run code in parallel without breaking it: threads, locks, executors… JVM34 lessons · How Java really runs: class loading, memory areas, garbage… Java 8 Course16 lessons · The release that changed how Java is written - lambdas, streams and… Java 21 Course15 lessons · The LTS that made cheap concurrency and real data modelling… Java 23 Course15 lessons · A non-LTS release about direction: gatherers, primitive patterns and… Java 25 Course16 lessons · The LTS where a decade of previews finally landed - and startup… Spring Boot39 lessons · Build a real REST service: beans, config, controllers, JPA, tests… Spring Security31 lessons · Lock down a Spring Boot app: filter chain, JWT, method security and… Hibernate32 lessons · Map Java objects to SQL tables with JPA and Hibernate, minus the… Kafka34 lessons · Topics, partitions, consumer groups and delivery guarantees, with… Microservices33 lessons · Design, connect and operate services that stay up when one of them… Docker31 lessons · Package a Java app into a small, safe container image and run it… Kubernetes32 lessons · Run containers in production: pods, deployments, services, scaling… System Design32 lessons · Scale, store and ship systems that stay up - and explain them in an… Kong Course15 lessons · API gateway patterns you learn by sending requests through it, not… MySQL Course21 lessons · Learn SQL by running it - a real query engine over a real dataset… OAuth 2.0 Course13 lessons · The delegation protocol, walked step by step - who redirects whom… JWT Authentication Course13 lessons · What is actually inside a token - decode it, edit a claim, watch… OAuth with Google9 lessons · A guided, end-to-end Google sign-in - the console setup, the real… GraphQL Course14 lessons · Ask for exactly the fields you need - and watch the response change… Redis Course19 lessons · Model data in Redis, cache without stampedes, lock without lying… Elasticsearch Course19 lessons · Model, index and query text properly - and know why your term query… RabbitMQ Course15 lessons · Route, acknowledge, retry and dead-letter messages on purpose - and… Jenkins CI/CD Course15 lessons · Write a Jenkinsfile you would actually ship - triggers, credentials…