Singleton Pattern in Java: Explanation & Practice

Implement the singleton design pattern

Problem summary

Create a Database class that can only have one instance. Return the same instance every time getInstance() is called.

Starter code

class Database {
    // Implement singleton pattern
    // Private static instance
    // Private constructor
    // Public static getInstance()
}

public class Main {
    public static void main(String[] args) {
        Database db1 = Database.getInstance();
        Database db2 = Database.getInstance();
        
        // Should print: Same instance: true
        System.out.println("Same instance: " + (db1 == db2));
    }
}

Expected output and test cases

Both references point to same instance
```
Same instance: true
```

Hints

Make constructor private
Create private static instance variable
Return instance in getInstance(), create if null

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