Java Singleton and Factory Patterns

Implement fundamental Gang of Four (GoF) object-oriented design patterns.

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Design patterns provide standard templates to solve software design problems: Singleton ensures a class has only one instance, while Factory decouples object creation from client code.

Key Takeaways: Java Singleton and Factory Patterns

Mastering Java Singleton and Factory Patterns helps you write clean and reliable Java code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.

Java Singleton and Factory Patterns Code Example

Java

class DatabaseConnection {
    private static DatabaseConnection instance;
    private DatabaseConnection() {}
    public static DatabaseConnection getInstance() {
        if (instance == null) instance = new DatabaseConnection();
        return instance;
    }
}

public class Main {
    public static void main(String[] args) {
        DatabaseConnection c1 = DatabaseConnection.getInstance();
        DatabaseConnection c2 = DatabaseConnection.getInstance();
        System.out.println("Same instance: " + (c1 == c2));
    }
}

Output

Same instance: true

Run this example on your own computer. The "Get Started" lesson shows how to set it up.

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Java Singleton and Factory Patterns

💡 Key Takeaways: Java Singleton and Factory Patterns

Java Singleton and Factory Patterns Code Example

Key Takeaways: Java Singleton and Factory Patterns