Uncommon Java Practices That Can Level Up Your Skills

Hidden Java Features That Make a Big Difference

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Java has a lot of hidden features and lesser-known techniques that can make your code cleaner, faster, and more efficient. While most developers stick to common practices, knowing these rare but powerful tricks can give you an edge in writing better Java applications.

1) Defining an Interface Inside a Class

An interface inside a class is called a nested interface.

class Outer {
    interface NestedInterface {
        void display();
    }
}

Unlike top-level interfaces, nested interfaces can have access control modifiers like private or protected.

Why & When to Use?

• Encapsulation — If an interface is only relevant to a particular class, keeping it inside that class hides it from the rest of the application.
• Stronger Design — It ensures only specific classes can implement the interface, enforcing modular design.
• Used in Event Handling — This is commonly used in Android and GUI-based applications.

class Button {
    interface ClickListener {
        void onClick();
    }

    private ClickListener listener;

    void…