Skip to main content

Java — Advanced

Understand Java deeply enough to optimize, secure, and operate it: the object and memory model, bytecode, reflection-driven design, the Java Memory Model, lock-free concurrency, virtual threads, GC and performance method, high-performance I/O, real loopback networking, persistence and distribution concepts, security, observability, and a production-grade capstone.

60 lessons0 challenges~18.75 hoursBeginner — no experience needed

Prerequisite course:Java — Intermediate

Who this course is for

Learners who finished Java — Intermediate and want JVM-level understanding: why Java behaves the way it does under load, concurrency, and failure — and how to engineer around it.

What you will be able to do

  • Explain and exploit Java's object model: initialization order, identity, records, sealed types
  • Read and reason about bytecode, constant pools, and compiler-generated constructs
  • Design type-safe generic APIs with variance, capture, and recursive bounds
  • Build metadata-driven systems with runtime annotations and reflection (a real mini DI container)
  • Apply the Java Memory Model: happens-before, volatile, safe publication, final-field semantics
  • Diagnose and fix races with locks, conditions, atomics, and CAS (including ABA)
  • Scale I/O-bound work with virtual threads and know when they do not help
  • Reason about allocation, reachability, and GC behavior; use weak references deliberately
  • Profile-by-reasoning with measurement discipline: warmup, JIT, and noise awareness
  • Implement advanced structures: tries, union-find, heaps, graph algorithms
  • Write real TCP clients/servers over loopback with correct framing and timeouts
  • Process files with NIO.2 channels and buffers, including memory-mapped reads
  • Design transactional persistence with isolation levels and optimistic concurrency
  • Apply distributed-systems primitives: idempotency, retries with backoff, circuit breaking
  • Harden code: password hashing, secure randomness, input validation, SSRF/path-traversal defense
  • Instrument services with structured logs, metrics, and health checks; run graceful shutdown
  • Ship a production-grade capstone integrating every layer of the course

The Advanced Object Model

Initialization order observed, records/sealed as algebraic design tools, and aliasing control at every boundary.

JVM Architecture & Bytecode

Runtime data areas, class-initialization triggers, constant-pool identity, boxing caches, synthetic members, and stack frames.

The Java Memory Model

Happens-before edges, volatile semantics, safe publication, and latch-choreographed determinism instead of timing luck.

Locks, Conditions & CAS

ReentrantLock's superpowers, per-predicate Condition queues, ConcurrentHashMap's atomic compute family, and CAS with ABA.

Executors & Virtual Threads

Executor lifecycle, CompletableFuture composition, virtual threads verified in-sandbox, pinning, and when VTs do not help.

Generics & the Type System

Erasure vs reified arrays, wildcard capture, recursive self-types, and Class-token APIs.

Reflection & the Mini-DI Container

Class metadata, runtime annotations, and a dependency-injection container built from the JDK alone.

Memory, GC & Runtime Internals

Reachability observed through its effects, allocation identity, and a GC-backed TTL cache.

Performance Measurement

nanoTime and warmup discipline, bounded bytecode claims, and an honest micro-benchmark harness.

Files & NIO

Path arithmetic, tree walking with globs, atomic moves, explicit charsets, and a JSONL journal.

Sockets & the Wire

Loopback TCP: streams without boundaries, framing, timeouts, half-close, and a KV protocol.

Async & Deadlines

Injected executors, exception-combinators, time-bounded futures, and deadline-scoped fan-outs.

Security & Threat Modeling

Canonicalization, constant-time auth, allowlists, least privilege, and threat models you can argue with.

Observability & Diagnosis

Structured logs, request context, metric primitives, and incident triage as pure functions.

Capstone: The Ledger Service

Pluggable storage engines, an append-only JSONL truth, and byte-identical polymorphic reports.