Module 03 · Object-Oriented Java

The heart of the exam (objective group 3): how Java models types and behavior — classes, inheritance and polymorphism, interfaces, enums, records, sealed types, nested classes, and modern pattern matching. This is the largest module; take the lessons in order, as each builds on the last.

Lessons

#	Lesson	What it covers
01	Classes & Objects	Fields/methods/constructors, this, static vs instance, init order, overloading.
02	Inheritance & Polymorphism	extends/super, overriding vs hiding, Object methods, casting, final.
03	Interfaces	Abstract/default/static/private methods, constants, the diamond conflict.
04	Enums	Fields/constructors/methods, values()/valueOf(), per-constant bodies, enums in switch.
05	Records	Components, canonical/compact constructors, accessors, immutability.
06	Sealed Types	sealed/permits, final/sealed/non-sealed, exhaustive switch.
07	Nested & Inner Classes	Static nested, inner, local, anonymous; capture rules.
08	Pattern Matching	instanceof patterns, switch patterns, record deconstruction, guards.

Track your progress

Your progress0 / 8 (0%)

• L01 — Classes & Objects
• L02 — Inheritance & Polymorphism
• L03 — Interfaces
• L04 — Enums
• L05 — Records
• L06 — Sealed Types
• L07 — Nested & Inner Classes
• L08 — Pattern Matching

Module Mini-Exam

A timed, mixed quiz covering the whole module. Aim well above the real exam's 68% pass bar.

Mini-Exam

• 12 questions
• 25 minutes
• 13 total points
• Pass: 9 pts (68%)