Java Exam Exercises — Model Solutions

This repository contains model solutions ("Musterlösungen") for all exam exercises from the course Programmieren mit Java.

Note: Exercise names and inline comments are in German; all Javadoc comments are in English.

Prerequisites

• Java 21
• Maven 3.x

Build & Test

# Compile
mvn clean compile

# Run all tests
mvn test

# Run a single test class
mvn test -Dtest=LibraryTest

# Run a single test method
mvn test -Dtest=LibraryTest#testFindBookByIsbn

# Build JAR
mvn clean package

Project Structure

src/
├── main/
│   ├── java/
│   │   ├── exams1/
│   │   │   ├── activitydiagrams/   # Implementations from UML activity diagrams
│   │   │   ├── classdiagrams/      # OOP design exercises
│   │   │   └── dicegames/          # Interactive dice game simulations
│   │   └── exams2/
│   │       ├── classdiagrams/      # Advanced OOP exercises with JUnit tests
│   │       └── queries/            # Stream API / collection query exercises
│   └── resources/                  # Data files (.txt, .csv) read by exercises
└── test/
    └── java/
        └── exams2/classdiagrams/   # JUnit 5 test classes (14 total)

Exercise Categories

Exam 1

Package	Description
exams1/activitydiagrams/	Algorithm implementations derived from UML activity diagrams (sorting algorithms, cash machine, discount calculator, timestamp converter)
exams1/classdiagrams/	12 OOP design exercises: cards dealer, cashier system, creatures, fast food, gift bag, parking garage, player, santa claus, shape, student course, travel booking, weather station, zoo
exams1/dicegames/	16 interactive dice game simulations, each with a MainClass entry point, a Player class, and game-logic classes

Exam 2

Package	Description
exams2/classdiagrams/	Advanced OOP exercises with full JUnit 5 test coverage: corner shop, dictionary, fantasy game, human resources, job offer, lego brick, library, player, shopping portal, shop, space station, superleague, team, video collection
exams2/queries/	Stream API exercises using filtering, sorting, and transforming collections (cities, measurement data, phone store, planets, singles, tanks)

Architecture Patterns

Each exercise is self-contained within its own sub-package. Common patterns used across the codebase:

• Records — immutable data types (e.g., Character, Planet, Book)
• Abstract classes with subclasses — type hierarchies (e.g., Shape, Book, Animal)
• Enums — type-safe constants (e.g., Profession, Race, Status)
• Lombok — @Data, @Getter, @AllArgsConstructor, etc. on mutable classes
• Java Streams — used heavily in exams2/queries/ exercises
• Comparable — implemented on records/classes that need natural ordering; a separate Comparator class is provided where multiple orderings are needed (e.g., LegoBrickVolumeComparator)
• Reader classes — parse semicolon-delimited .txt files from src/main/resources/ using Scanner with hasNextLine() / nextLine()

Dependencies

Dependency	Version	Scope
Lombok	1.18.36	compile
JUnit Jupiter	5.11.3	test
Mockito	5.14.2	test