Module 05 · Generics, Arrays & Collections

Objective group 5: the data-structure toolkit — arrays, generics and wildcards, the Collections Framework, Java 21's Sequenced Collections, and ordering with Comparable/Comparator. Plenty of behavioral traps (array covariance, PECS, immutable factories, TreeSet equality) live here.

Lessons

#	Lesson	What it covers
01	Arrays	Declaration/init, multidimensional & jagged, Arrays utility, covariance.
02	Generics	Type parameters, bounds, wildcards (PECS), type erasure.
03	Core Collections	List/Set/Map/Deque, implementations, factory methods, safe removal.
04	Sequenced Collections	SequencedCollection/Set/Map, reversed(), getFirst/getLast (Java 21).
05	Comparison & Sorting	Comparable, Comparator chaining, contracts, TreeSet equality.

Track your progress

Your progress0 / 5 (0%)

• L01 — Arrays
• L02 — Generics
• L03 — Core Collections
• L04 — Sequenced Collections
• L05 — Comparison & Sorting

Module Mini-Exam

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

Mini-Exam

• 9 questions
• 20 minutes
• 10 total points
• Pass: 7 pts (68%)