Lambda Expressions

Lambda expressions provide a concise way to represent anonymous functions, introduced in Java 8.
Commonly used with functional interfaces (interfaces with a single abstract method).
Benefits:
- Reduces boilerplate code.
- Enhances readability and maintainability.
- Simplifies operations on collections and functional interfaces.

Basic SyntaxUsing with CollectionsMethod ReferencesFunctional Interfaces

Syntax: (parameters) -> expression or (parameters) -> { statements }
Example:

interface Greeting {
    void sayHello(String name);
}

public class Main {
    public static void main(String[] args) {
        Greeting greeting = (name) -> System.out.println("Hello, " + name + "!");
        greeting.sayHello("John"); // Outputs: Hello, John!
    }
}

Simplifies operations like filtering, mapping, and iterating.

import java.util.Arrays;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<String> names = Arrays.asList("Alice", "Bob", "Charlie");

        names.stream()
             .filter(name -> name.startsWith("A"))
             .forEach(System.out::println); // Outputs: Alice
    }
}

Method references provide a shorthand notation for calling methods using ClassName::methodName.

import java.util.Arrays;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<String> names = Arrays.asList("Alice", "Bob", "Charlie");

        names.forEach(System.out::println); // Outputs: Alice Bob Charlie
    }
}

Compatible with functional interfaces like Predicate, Function, Consumer, and Supplier.

import java.util.function.Predicate;

public class Main {
    public static void main(String[] args) {
        Predicate<Integer> isEven = n -> n % 2 == 0;
        System.out.println(isEven.test(4)); // Outputs: true
    }
}