Lambda Expressions are the most remarkable feature added to the Java platform with Java 8.   It's specified in JSR 335  and JEP 126 . The very need for this feature is to gain the capabilities supplied by functional programming. The main idea behind this concept is to be able to parametrize the functions for subsequent executions of them. Till Java 8, this can be simulated via the use of anonymous inner classes with some design patterns like command pattern and functors. However the adoption of lambda expressions gave way to the direct use of this concept. 1. What is a Lambda Expression ? A lambda expression is a piece of code that is giving an alternative way to the anonymous class to pass the function as parameter to other methods, constructors and etc..  In this approach, a function can be referenced with a variable and passed as reference to be executed in a