Lesson 1: Advanced OOP
Records, classes, enums, sealed interfaces, generics, pricing rules, validation, sorting, grouping, and domain invariants.
Lessons
Each lesson page combines learner instructions, instructor notes, commands, edge-case guidance, and all related function pages.
Lesson 2: Decorator Usage
Object decorators, Java I/O decorators, functional wrappers, wrapper order, side effects, blocklists, truncation, counting, and composition.
Lesson 3: Multi-Threading
Executors, futures, CompletableFuture, virtual threads, atomic counters, deterministic aggregation, top-N ranking, and ordered parallel results.
Lesson 4: Toy Edge Detect Library
Image matrices, grayscale conversion, convolution, Sobel edge detection, pixel math, normalization, clamped sampling, and PNG output.
Lesson 5: Java @ Annotations
All major Java @ use cases: built-ins, custom annotations, meta-annotations, repeatable annotations, type-use annotations, package and record targets, decorator-style metadata, getter/setter metadata, and reflection.
Lesson 6: Spring Boot Hello World
A first Spring Boot web app with Maven, @SpringBootApplication, @RestController, query parameters, JSON POST requests, configuration properties, service validation, error handling, and tests.