What design patterns are used in Java for application development?

In Java, the following design patterns are often used for application development:

• Singleton — to ensure a class has only one instance.
• Factory Method — to create objects without specifying the exact class.
• Observer — to implement subscription and notification of changes.
• Decorator — to dynamically add functionality to objects.
• MVC (Model-View-Controller) — to separate logic, presentation, and control.

Example of Singleton:

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