1. Phase 1. Where to start

    Why this course exists and who it fits: the problem it solves, how phases, tests and trainers work, and how to go through it without dropping off.

  2. Phase 2. Language basics: Java · 70 questions

    Syntax and types, OOP, collections, generics, exceptions, lambdas and Stream API, modern Java, tooling — language foundations before frameworks.

  3. Phase 3. Algorithms and data structures · 52 questions

    Arrays and Big-O, sorting, stacks and queues, lists, recursion, trees, hash tables, heaps and graphs — the foundation under collections, indexes and stores.

  4. Phase 4. Git and branching models · 24 questions

    Snapshots and commits, branches and merging, push/pull, pull requests and code review, rebase and reflog, branching models from Git Flow to trunk-based.

  5. Phase 5. Foundation: Spring core · 37 questions

    DI/IoC, bean lifecycle, Boot, MVC, Data JPA, transactions, events, AOP, scheduler.

  6. Phase 6. Multithreading and concurrency · 36 questions

    Threads and the Java memory model (JMM, happens-before, volatile), race conditions, synchronized and explicit locks, atomics and CAS, thread-safe collections, thread pools, CompletableFuture, Java 21 virtual threads, and common bugs — deadlock, livelock, starvation.

  7. Phase 7. Design principles and patterns · 26 questions

    SOLID, GRASP, GoF patterns, DRY/KISS/YAGNI.

  8. Phase 8. SQL from scratch · 40 questions

    The query language before any particular database: tables and keys, SELECT and WHERE, joins, aggregates, NULL, subqueries, window functions, dates and strings, modifying data, creating tables and why a query suddenly got slow.

  9. Phase 9. PostgreSQL: model and queries · 63 questions

    Transactions and isolation, locking, data types, indexes and EXPLAIN.

  10. Phase 10. PostgreSQL: operations and scale · 69 questions

    Migrations, connection pool, vacuum/WAL, replication, backup, partitioning, FTS and geo.

  11. Phase 11. Hibernate and ORM · 33 questions

    Object-relational mapping: mapping entities and associations, persistence context, lazy loading and N+1, JPQL and Criteria, caching, transactions and locking, inheritance and common pitfalls.

  12. Phase 12. Other stores: documents, search, files, analytics · 156 questions

    First the foundations — storage engines, replication, sharding, streams. Then the stores themselves: MongoDB, Elasticsearch, object storage (S3) and ClickHouse.

  13. Phase 13. Networking fundamentals · 40 questions

    OSI and TCP/IP models, IP and ports, TCP/UDP, DNS, HTTP and HTTPS, HTTP versions, connections and reliability.

  14. Phase 14. API: REST and contracts · 94 questions

    URLs and resources, query parameters, responses and errors, versioning, OpenAPI.

  15. Phase 15. Security and authorization · 49 questions

    Spring Security, Keycloak/OAuth2/OIDC and authorization patterns.

  16. Phase 16. Brokers and distributed systems · 66 questions

    AMQP/RabbitMQ, Kafka and distributed patterns: saga, outbox, idempotency.

  17. Phase 17. Microservices: architecture and pitfalls · 53 questions

    Whether you need microservices, how a service is structured and how they communicate; what breaks in a distributed system and how to fix it — saga, outbox, idempotency, resilience.

  18. Phase 18. Containers: Docker · 38 questions

    Containers and images, Dockerfile for Spring Boot, multi-stage builds, running containers, volumes and data, networking, Docker Compose, the JVM in a container, secure images and registries.

  19. Phase 19. Kubernetes and graceful shutdown · 59 questions

    Cluster, networking, Spring Boot on Kubernetes, deployment and graceful shutdown.

  20. Phase 20. Clouds · 141 questions

    Cloud principles and three providers — AWS, Azure and GCP: networking, IAM, compute, scaling, serverless, data, storage and IaC. One model, knowledge transfers between clouds.

  21. Phase 21. CI/CD: the delivery pipeline · 30 questions

    Pipeline principles, CI for Java, release strategies and branching.

  22. Phase 22. Quality: test strategy · 32 questions

    The test pyramid, slices and integration tests, mocks and external services, load testing.

  23. Phase 23. Observability and diagnostics · 62 questions

    How to see what a running system is doing: logs, metrics, tracing, context propagation, health checks, SLOs and alerts — plus database diagnostics and the incident review afterwards.

  24. Phase 24. Working with AI agents · 36 questions

    How a language model works and how to write code productively with an AI agent: tokens and hallucinations, context, tool calling, agents, the working loop, reviewing and accepting AI code.

  25. Phase 25. Building LLM applications · 32 questions

    How to embed AI into a backend product: what an LLM feature is made of, orchestration with LangChain, RAG and embeddings, vector databases, and agent applications.

  26. Phase 26. System design and architectural choices · 56 questions

    The design method, building blocks, storage and notation choices, C4.

  27. Phase 27. Domain-Driven Design · 26 questions

    Strategic and tactical DDD patterns, aggregates, domain events.

  28. Phase 28. Service architecture patterns · 67 questions

    Service and microservice structure, Onion and Hexagonal, CQRS, resilience and batch processing.

  29. Phase 29. Development methodologies and process · 19 questions

    Waterfall, Agile, Scrum, Kanban, XP, estimation and scaling — how a team organizes work from idea to release.

  30. Phase 30. Kotlin for the Java developer · 39 questions

    A second JVM language: syntax and idioms, null-safety, data and sealed classes, extension functions, coroutines vs virtual threads, and Spring Boot with Kotlin. Optional phase.

  31. Phase 31. The product engineer: role and practice · 43 questions

    The whole role: start from the user problem, outcome metrics and end-to-end ownership — plus working with an AI agent, the domain model and the path from slice to contract.

  32. Phase 32. Use Case Pattern and the end-to-end case · 34 questions

    The culmination: the Use Case Pattern methodology — designing a service from the business task, the Use Case spec, maturity levels 0–3 — and the end-to-end marketplace case that ties the whole path together.