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Java Foundations

Learn to read, reason about, and write Java — the language that runs the enterprise.

📚 61 lessons 🧩 10 phases ▶ Runs real Java code
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A read-and-reason Java course. Unlike our Python, JavaScript, and SQL courses, this one does not run your code in the browser — and we tell you that up front rather than faking it. Instead you build the skill that senior engineers actually use most: reading Java carefully and predicting exactly what it will do. Every code sample is real, compiling Java.

Module 1 · Getting Started & Mental Models

How Java is built, compiled, and executed.

  1. Why Java — and How This Course Works 19 min
  2. JDK vs JRE vs JVM (and Classpath Basics) 19 min
  3. Your First Java Program (main, println) 19 min
  4. From .java to .class: Compilation, Bytecode, Runtime 19 min
  5. Compile Errors vs Runtime Errors (Stack Traces) 19 min
  6. IDE Workflow + Build Tools Overview 20 min

Module 2 · Core Syntax & Types

The building blocks: types, operators, text, and numbers.

  1. Variables & Types 19 min
  2. Operators & Expressions 19 min
  3. Strings & Text 19 min
  4. Numeric Types, Casting, and Overflow 19 min
  5. Formatting Output (printf, format specifiers) 19 min
  6. Ternary and Compound Assignment Operators 18 min

Module 3 · Control Flow & Program Structure

Decisions, loops, and the paths a program takes.

  1. Control Flow 18 min
  2. Boolean Logic & Short-Circuiting 19 min
  3. Switch Statements, Switch Expressions, and Enums 19 min
  4. Loop Patterns and Invariants 19 min
  5. break/continue and Labeled Loops 19 min
  6. Arrays and Iteration 19 min

Module 4 · Methods & Modularity

Reusable logic, decomposition, and recursion.

  1. Methods 19 min
  2. Parameters, Returns, and Overloading 18 min
  3. Scope, Lifetime, and Shadowing 18 min
  4. Recursion Basics (base case, call stack) 18 min
  5. Pass-by-Value: Primitives vs References 19 min
  6. Immutability, Side Effects, Defensive Copying 19 min

Module 5 · Object-Oriented Fundamentals

Model problems with classes, objects, and encapsulation.

  1. Classes & Objects 18 min
  2. Constructors and Initialization Order 18 min
  3. Encapsulation and Access Modifiers 18 min
  4. static Members, Constants, Utility Classes 18 min
  5. equals, hashCode, and toString Contracts 18 min
  6. Packages, Imports, and Project Layout 18 min

Module 6 · Inheritance, Polymorphism & Design

Polymorphism, interfaces, and sound object-oriented design.

  1. Inheritance & Interfaces 19 min
  2. Polymorphism and Dynamic Dispatch 19 min
  3. Abstract Classes vs Interfaces (default methods) 19 min
  4. Composition Over Inheritance (Delegation) 19 min
  5. Nested Classes and Lambdas Intro 19 min
  6. OOP Design Principles (SRP, OCP, LSP) 18 min

Module 7 · Collections & Generics

Collections, generics, and practical performance trade-offs.

  1. Collections 18 min
  2. Generics Fundamentals 19 min
  3. List vs Set vs Map: Choosing the Right Type 19 min
  4. Iteration: for-each, Iterators, ConcurrentModification 18 min
  5. Comparators and Sorting (Comparable vs Comparator) 19 min
  6. Big-O and Collections Performance 19 min

Module 8 · Exceptions, I/O & Resources

Handle failure robustly and manage resources correctly.

  1. Exception Hierarchy and try/catch/finally 19 min
  2. Checked vs Unchecked Exceptions 18 min
  3. try-with-resources and AutoCloseable 18 min
  4. Designing Custom Exceptions 19 min
  5. File I/O with java.nio.file (overview) 19 min
  6. Serialization and Data Formats (Java vs JSON) 19 min

Module 9 · Modern Java: Functional Style & Concurrency

Streams, lambdas, Optional, and safe concurrency.

  1. Functional Interfaces and Lambdas 19 min
  2. Stream API Core Operations (map, filter, reduce) 19 min
  3. Collectors and Grouping 19 min
  4. Optional and Null-Safety Practices 19 min
  5. Threads and Executors (Concepts) 19 min
  6. Synchronization, Atomicity, Concurrency Hazards 19 min

Module 10 · Capstone: Professional Java Project

Apply everything to a realistic project, milestone by milestone.

  1. Capstone Kickoff: Requirements and Domain Model 20 min
  2. Milestone 1: Core Domain Classes 20 min
  3. Milestone 2: In-Memory Data + Search/Sort 20 min
  4. Milestone 3: Interfaces for Extensibility 19 min
  5. Milestone 4: Robust Error Handling 19 min
  6. Milestone 5: Reporting with Streams 20 min
  7. Milestone 6: Retrospective + Interview Readiness 19 min