Lambda Expressions

A Lambda expression is a new feature in Java 8 that enables it to treat a function as method arguments and a concise code representation of an anonymous function that can be passed. Anonymous means no name, as it is a function with anonymous it can have parameters too. A lambda expression is commonly used to implement simple events listeners/ callbacks, or in functional programming or we can say, It's used to provide the implementation of a functional interface.

    A lambda expression is an anonymous function that has a body, return type, arguments, and exceptions.

    Syntax:-     

• (parameters) -> expression
• (parameters) -> { statements; }

    Example:-

• () -> "codeforsolution";
• () -> {};
• (String str) -> str.lenght();
• () -> System.out.println("Code for solution");
• (a, b) -> a.toUpperCase + b.toUpperCase();
• (a, b) ->  System.out.println(a+b); 

Example:- 

Without lambda Expression.

       

Runnable runnable = new Runnable() {
    @Override
    public void run() {
        System.out.println("Run method from Runnable");
    }
};
new Thread(runnable).start();

With Lambda Expression.

Runnable runnable = () -> System.out.println("Run method from Runnable");
new Thread(runnable).start();

Comparator Without Lambda Expression

Comparator<Integer> comparator = new Comparator<Integer>() {
    @Override
    public int compare(Integer o1, Integer o2) {
        return o1.compareTo(o2);
    }
};

With Lambda Expression

Comparator<Integer> comparator = (o1, o2) -> o1.compareTo(o2);