CouplingExamples.java

// Tight Coupling Example
class Database {
    public User getUser(int userId) {
        // database logic here
        return new User(userId);
    }
}

class UserService {
    private Database db;

    public UserService() {
        this.db = new Database();
    }

    public User getUserInfo(int userId) {
        return db.getUser(userId);
    }
}

// Loose Coupling Example
class LooselyCoupledUserService {
    private Database db;

    public LooselyCoupledUserService(Database database) {
        this.db = database;
    }

    public User getUserInfo(int userId) {
        return db.getUser(userId);
    }
}

// Decoupling with Interfaces Example
interface DatabaseInterface {
    User getUser(int userId);
}

class DatabaseImpl implements DatabaseInterface {
    public User getUser(int userId) {
        // database logic here
        return new User(userId);
    }
}

class DecoupledUserService {
    private DatabaseInterface db;

    public DecoupledUserService(DatabaseInterface database) {
        this.db = database;
    }

    public User getUserInfo(int userId) {
        return db.getUser(userId);
    }
}

// Helper class for the examples
class User {
    private int id;

    public User(int id) {
        this.id = id;
    }
}

public class CouplingExamples {
    public static void main(String[] args) {
        // Tight Coupling
        UserService tightlyCoupleddService = new UserService();
        User user1 = tightlyCoupleddService.getUserInfo(1);

        // Loose Coupling
        Database database = new Database();
        LooselyCoupledUserService looselyCoupleddService = new LooselyCoupledUserService(database);
        User user2 = looselyCoupleddService.getUserInfo(2);

        // Decoupling with Interfaces
        DatabaseInterface databaseInterface = new DatabaseImpl();
        DecoupledUserService decoupledService = new DecoupledUserService(databaseInterface);
        User user3 = decoupledService.getUserInfo(3);

        System.out.println("Coupling examples created successfully.");
    }
}