Can you give examples of interface types used in Java to define contracts between components?

In Java, interfaces are used to define contracts between components, meaning they describe a set of methods that a class must implement. Examples of interface types:

• Functional interfaces — contain a single abstract method, used for lambda expressions and functional programming. For example, Runnable, Callable, Comparator.

• Marker interfaces — contain no methods, used to mark classes, e.g., Serializable, Cloneable.

• API interfaces — describe the behavior of components, e.g., List, Map, Set in collections.

Example of a functional interface:

@FunctionalInterface
public interface Calculator {
    int calculate(int a, int b);
}

// Usage
Calculator sum = (a, b) -> a + b;
int result = sum.calculate(5, 3); // 8

Interfaces enable the creation of flexible and extensible architectures, ensuring loose coupling between components.