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Java Lab Exercises: Trip Management Application

Complete Guide to Arrays, Strings, and OOP Basics

Lab Overview

In this comprehensive lab series, you'll build a Trip Management Application that helps users plan and manage their travel itineraries. Through this project, you'll master fundamental Java concepts including Arrays, Strings, and Object-Oriented Programming principles.

Lab 1: Arrays in Java

Definition

Arrays in Java are data structures that store multiple elements of the same type in a contiguous memory location. They provide indexed access to elements and have a fixed size once declared.

Key Concepts

  • Declaration: dataType[] arrayName or dataType arrayName[]
  • Initialization: new dataType[size] or {element1, element2, ...}
  • Access: arrayName[index] (0-based indexing)
  • Length: arrayName.length

Example: Basic Trip Destinations Array

public class TripDestinations {
    public static void main(String[] args) {
        // Declaration and initialization
        String[] destinations = {"Paris", "Tokyo", "New York", "London", "Sydney"};
        
        // Alternative way
        String[] popularDestinations = new String[5];
        popularDestinations[0] = "Rome";
        popularDestinations[1] = "Barcelona";
        popularDestinations[2] = "Amsterdam";
        popularDestinations[3] = "Bangkok";
        popularDestinations[4] = "Dubai";
        
        // Display destinations
        System.out.println("Available Destinations:");
        for(int i = 0; i < destinations.length; i++) {
            System.out.println((i+1) + ". " + destinations[i]);
        }
        
        // Enhanced for loop
        System.out.println("\nPopular Destinations:");
        for(String destination : popularDestinations) {
            System.out.println("- " + destination);
        }
    }
}

MCQ Questions

Question 1: What is the correct way to declare an array of integers in Java? A) int array[]; B) int[] array; C) array int[]; D) Both A and B

Answer: D - Both int array[] and int[] array are valid declarations.

Question 2: What will be the output of the following code?

int[] numbers = {10, 20, 30, 40};
System.out.println(numbers.length);

A) 3 B) 4 C) 40 D) Compilation error

Answer: B - The array has 4 elements, so length returns 4.

Tasks

Task 1: Trip Expense Tracker Create a program that:

  • Stores daily expenses for a 7-day trip in an array
  • Calculates total expenses
  • Finds the day with maximum expense
  • Calculates average daily expense

Task 2: Multi-Destination Trip Planner Create a program that:

  • Uses a 2D array to store trip information (destination, duration in days, estimated cost)
  • Allows user to add new trips
  • Displays all planned trips in a formatted table
  • Calculates total trip duration and cost

Lab 2: Strings in Java

Definition

Strings in Java are objects that represent sequences of characters. They are immutable, meaning once created, their value cannot be changed. Java provides extensive methods for string manipulation.

Key Concepts

  • Immutability: Strings cannot be modified after creation
  • String Pool: Java maintains a pool of string literals for memory efficiency
  • Common Methods: length(), charAt(), substring(), indexOf(), toUpperCase(), toLowerCase(), trim(), split(), equals(), compareTo()

Example: Trip Information Processing

public class TripStringOperations {
    public static void main(String[] args) {
        String tripInfo = "  Paris-France-5days-1500USD  ";
        
        // Basic operations
        System.out.println("Original: '" + tripInfo + "'");
        System.out.println("Length: " + tripInfo.length());
        System.out.println("Trimmed: '" + tripInfo.trim() + "'");
        
        // Processing trip details
        String cleanInfo = tripInfo.trim();
        String[] details = cleanInfo.split("-");
        
        System.out.println("\nTrip Details:");
        System.out.println("Destination: " + details[0]);
        System.out.println("Country: " + details[1]);
        System.out.println("Duration: " + details[2]);
        System.out.println("Cost: " + details[3]);
        
        // String formatting
        String formattedTrip = String.format("Trip to %s, %s for %s costs %s", 
                                           details[0], details[1], details[2], details[3]);
        System.out.println("\nFormatted: " + formattedTrip);
        
        // String comparison
        String destination1 = "Paris";
        String destination2 = "paris";
        System.out.println("\nCase sensitive comparison: " + destination1.equals(destination2));
        System.out.println("Case insensitive comparison: " + destination1.equalsIgnoreCase(destination2));
    }
}

MCQ Questions

Question 1: Which method is used to compare two strings for equality in Java? A) == B) equals() C) compareTo() D) compare()

Answer: B - equals() method compares the actual content of strings.

Question 2: What is the result of the following code?

String str = "Hello World";
System.out.println(str.substring(6, 11));

A) World B) Worl C) orld D) World!

Answer: A - substring(6, 11) extracts characters from index 6 to 10 (end index is exclusive).

Tasks

Task 1: Trip Itinerary Parser Create a program that:

  • Takes a trip itinerary string like "Day1:Museum,Day2:Beach,Day3:Shopping"
  • Parses and displays each day's activities
  • Counts total activities
  • Allows searching for specific activities

Task 2: Travel Document Validator Create a program that:

  • Validates passport numbers (format: 2 letters + 6 digits)
  • Checks email format for booking confirmations
  • Formats traveler names (proper case)
  • Generates booking reference codes

Lab 3: Object-Oriented Programming Basics

Definition

Object-Oriented Programming (OOP) is a programming paradigm based on the concept of objects, which contain data (attributes) and code (methods). The four main principles are Encapsulation, Inheritance, Polymorphism, and Abstraction.

Key Concepts

  • Class: Blueprint for creating objects
  • Object: Instance of a class
  • Encapsulation: Bundling data and methods, hiding internal details
  • Inheritance: Creating new classes based on existing ones
  • Polymorphism: Same interface, different implementations
  • Abstraction: Hiding complex implementation details

Example: Trip Management System Classes

// Base class for all trip-related entities
class Trip {
    // Private fields (Encapsulation)
    private String destination;
    private int duration;
    private double cost;
    private String travelerName;
    
    // Constructor
    public Trip(String destination, int duration, double cost, String travelerName) {
        this.destination = destination;
        this.duration = duration;
        this.cost = cost;
        this.travelerName = travelerName;
    }
    
    // Getter methods (Encapsulation)
    public String getDestination() { return destination; }
    public int getDuration() { return duration; }
    public double getCost() { return cost; }
    public String getTravelerName() { return travelerName; }
    
    // Setter methods (Encapsulation)
    public void setDestination(String destination) { this.destination = destination; }
    public void setDuration(int duration) { this.duration = duration; }
    public void setCost(double cost) { this.cost = cost; }
    public void setTravelerName(String travelerName) { this.travelerName = travelerName; }
    
    // Method to display trip information
    public void displayTripInfo() {
        System.out.println("=== Trip Information ===");
        System.out.println("Traveler: " + travelerName);
        System.out.println("Destination: " + destination);
        System.out.println("Duration: " + duration + " days");
        System.out.println("Cost: $" + cost);
    }
    
    // Method to calculate cost per day
    public double getCostPerDay() {
        return cost / duration;
    }
}

// Specialized trip class (Inheritance)
class BusinessTrip extends Trip {
    private String company;
    private boolean isReimbursable;
    
    public BusinessTrip(String destination, int duration, double cost, 
                       String travelerName, String company, boolean isReimbursable) {
        super(destination, duration, cost, travelerName); // Call parent constructor
        this.company = company;
        this.isReimbursable = isReimbursable;
    }
    
    public String getCompany() { return company; }
    public boolean isReimbursable() { return isReimbursable; }
    
    // Method overriding (Polymorphism)
    @Override
    public void displayTripInfo() {
        super.displayTripInfo(); // Call parent method
        System.out.println("Company: " + company);
        System.out.println("Reimbursable: " + (isReimbursable ? "Yes" : "No"));
    }
}

// Another specialized trip class
class VacationTrip extends Trip {
    private String[] activities;
    private String accommodationType;
    
    public VacationTrip(String destination, int duration, double cost, 
                       String travelerName, String[] activities, String accommodationType) {
        super(destination, duration, cost, travelerName);
        this.activities = activities;
        this.accommodationType = accommodationType;
    }
    
    public String[] getActivities() { return activities; }
    public String getAccommodationType() { return accommodationType; }
    
    @Override
    public void displayTripInfo() {
        super.displayTripInfo();
        System.out.println("Accommodation: " + accommodationType);
        System.out.print("Activities: ");
        for(int i = 0; i < activities.length; i++) {
            System.out.print(activities[i]);
            if(i < activities.length - 1) System.out.print(", ");
        }
        System.out.println();
    }
}

// Main class to demonstrate OOP concepts
public class TripManagementSystem {
    public static void main(String[] args) {
        // Creating objects
        Trip generalTrip = new Trip("London", 5, 2000.0, "John Doe");
        BusinessTrip businessTrip = new BusinessTrip("Tokyo", 3, 3000.0, 
                                                     "Jane Smith", "TechCorp", true);
        
        String[] activities = {"Sightseeing", "Beach", "Museum", "Local Cuisine"};
        VacationTrip vacationTrip = new VacationTrip("Bali", 7, 1800.0, 
                                                     "Mike Johnson", activities, "Resort");
        
        // Demonstrating polymorphism
        Trip[] allTrips = {generalTrip, businessTrip, vacationTrip};
        
        for(Trip trip : allTrips) {
            trip.displayTripInfo(); // Calls appropriate overridden method
            System.out.println("Cost per day: $" + String.format("%.2f", trip.getCostPerDay()));
            System.out.println();
        }
    }
}

MCQ Questions

Question 1: Which OOP principle is demonstrated when a class hides its internal data and provides public methods to access it? A) Inheritance B) Polymorphism C) Encapsulation D) Abstraction

Answer: C - Encapsulation involves hiding internal data and providing controlled access through methods.

Question 2: In Java, what keyword is used to inherit from a parent class? A) implements B) extends C) inherits D) super

Answer: B - The extends keyword is used for class inheritance in Java.

Tasks

Task 1: Complete Trip Booking System Create a comprehensive system with:

  • Traveler class with personal information
  • Booking class that manages trip reservations
  • Hotel and Flight classes for different services
  • Methods to calculate total booking cost
  • Booking confirmation and cancellation features

Task 2: Trip Review and Rating System Develop a system that includes:

  • Review class with rating, comment, and reviewer details
  • Destination class that aggregates reviews
  • Methods to calculate average ratings
  • Feature to filter reviews by rating
  • Display top-rated destinations

Integration Project: Complete Trip Management Application

Final Challenge

Combine all concepts learned to create a complete Trip Management Application that includes:

  1. Array Management: Store multiple trips, travelers, and destinations
  2. String Processing: Handle user input, format outputs, validate data
  3. OOP Implementation: Use proper class design with inheritance and polymorphism

Application Features

  • Add new trips (business or vacation)
  • View all trips with formatted display
  • Search trips by destination or traveler
  • Calculate trip statistics (total cost, average duration)
  • Generate trip reports
  • Manage traveler profiles

Sample Output

=== Trip Management System ===
1. Add New Trip
2. View All Trips  
3. Search Trips
4. Trip Statistics
5. Generate Report
6. Exit

Enter your choice: 2

=== All Trips ===
Trip #1:
Traveler: John Doe
Destination: London
Duration: 5 days
Cost: $2000.00
Cost per day: $400.00
Type: General Trip

Trip #2:
Traveler: Jane Smith  
Destination: Tokyo
Duration: 3 days
Cost: $3000.00
Cost per day: $1000.00
Type: Business Trip
Company: TechCorp
Reimbursable: Yes

Learning Outcomes

After completing these labs, students will be able to:

  1. Arrays: Declare, initialize, and manipulate single and multi-dimensional arrays
  2. Strings: Perform string operations, parsing, and validation
  3. OOP Basics: Design classes, implement inheritance, and use polymorphism
  4. Integration: Combine multiple concepts to build real-world applications
  5. Problem Solving: Break down complex problems into manageable components

Best Practices Learned

  • Proper naming conventions
  • Code organization and structure
  • Error handling techniques
  • Memory management considerations
  • Documentation and commenting
  • Testing and debugging strategies

Next Steps

  • Advanced OOP concepts (Abstract classes, Interfaces)
  • Exception handling
  • File I/O operations
  • Collections Framework
  • GUI development with Swing/JavaFX