Foundations

15 labs from your first Hello World to a complete inventory system using OOP, streams, generics, concurrency, and NIO.2.

#	Lab	Key Concepts
1	Hello World & Java Basics	compile, JVM, main method, System.out
2	Variables & Primitives	int, double, char, boolean, casting
3	Strings & StringBuilder	String methods, immutability, StringBuilder
4	Arrays	arrays, 2D arrays, Arrays utility, sorting
5	Control Flow & Recursion	switch expressions, loops, recursion, FizzBuzz
6	OOP — Classes & Encapsulation	fields, constructors, records, Builder pattern
7	Inheritance & Polymorphism	extends, override, super, sealed classes
8	Interfaces & Abstract Classes	interface, default/static methods, functional, Strategy/Observer
9	Collections	ArrayList, HashSet, HashMap, PriorityQueue
10	Exception Handling	checked/unchecked, custom hierarchy, chaining, Result type
11	File I/O — NIO.2	Path, Files, walk, WatchService, log analyzer
12	Generics	type parameters, bounds, wildcards, PECS, repository
13	Streams & Lambdas	filter/map/collect, groupingBy, flatMap, parallel, sales pipeline
14	Concurrency Basics	threads, ExecutorService, CompletableFuture, virtual threads
15	Capstone — Inventory System	all concepts combined, CLI app, CSV persistence

Runtime: Java 21 (Eclipse Temurin) · Docker: zchencow/innozverse-java:latest

🐳 Quick Start

docker run --rm zchencow/innozverse-java:latest java -e 'class H{public static void main(String[]a){System.out.println("Hello, Java 21!");}}'