Answer» - A Lambda expression is a function that can be created without including it in any class. It was introduced in Java 8.
- It is used to provide the interface implementation which has a functional interface. It does not require defining the method again for providing the implementation, it is allowed to just write the implementation code. Thus it saves plenty of coding.
- Lambda expression is considered as a function, the .class file will not be created by the compiler.
- They are generally used for simple callbacks or event listeners implementation, or in functional programming with the Java Streams API.
- Lambda Expression Syntax is:
(argument_list) -> {body}
THREE components of Lamda expression are:- argument_list: Zero or more number of arguments.
- -> (arrow-token): Used to link argument_list and body of lambda expression.
- body: CONTAINS statements and expressions for lambda expression.
- A Java example program to ILLUSTRATE lambda expressions by implementing the user-defined functional interface is given below:
// A functional interface with a single abstract method. interface ExampleInterface{ // An abstract method void abstractPrint(int a);}class InterviewBit{ public static void main(String args[]) { /* A lambda expression to implement the above functional interface. */ ExampleInterface OB = (int a)->{System.out.println(a)}; // This calls above lambda expression and prints 20. ob.abstractPrint(20); }}In the above example program, Example Interface is the functional interface that has a single abstract method abstractPrint(). By using lambda expression within InterviewBit class, we are implementing the functional interface by providing implementation code for the abstract method within an interface.
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