Java is among the most popular technologies in the software world and has recently come out with new releases, such as, Java ver 11 and ver 12. However, Java ver 8 continues to remain at the forefront of many new technology initiatives. Java 8 released on 18 March 2014 by Oracle with Java SE 8 Platform include JDK-8 and JRE-8.

Java 8 offers features such as bug fixing, security enhancement and overall improves the efficiency of development.

There are Core features of Java 8

  • Lambda expressions
  • Method references
  • Stream API
  • Collectors class
  • ForEach() method
  • IO Enhancements
  • Default methods
  • Functional interfaces
  • Parallel array sorting
  • Static methods in interface
  • Optional class
  • Nashorn JavaScript Engine
  • Parallel Array Sorting
  • JDBC Enhancements
  • Type and Repeat Annotations
  • Concurrency Enhancement

What is Lambda expression?

Java Lambda is one of the essential features of Java 8 that represents one method interface by the help of an expression. Java Lambda expression allow developers to write the code in a functional style. Therefore, it saves considerable time and effort of the developer. With Java Lambda, the developers do not need to define the method repeatedly.

The most essential feature of Java Lambda is “they execute in the context of their appearance”.

java lambda expressions

Syntax of Java Lambda Expression

(parameter_list) -> {function_body}

Java lambda expression comprises three components.

1) Parameter_list: It may be empty or non-empty

2) Lambda operator: It is Arrow-token (->) used to link Parameter_list and Function_Body.

3) Function_Body: It contains expressions and statements for Lambda expression.

Here demonstration of lambda expression with two arguments.

l
public class Test
{
// operation is implemented using lambda expressions
interface FuncInter1
{
int operation(int a, int b);
}
// sayMessage() is implemented using lambda expressions
// above
interface FuncInter2
{
void sayMessage(String message);
}
// Performs FuncInter1's operation on 'a' and 'b'
private int operate(int a, int b, FuncInter1 fobj)
{
return fobj.operation(a, b);
}
public static void main(String args[])
{
// lambda expression for addition for two parameters
// data type for x and y is optional.
// This expression implements 'FuncInter1' interface
FuncInter1 add = (int x, int y) -> x + y;
// lambda expression multiplication for two parameters
// This expression also implements 'FuncInter1' interface
FuncInter1 multiply = (int x, int y) -> x * y;
// Creating an object of Test to call operate using
// different implementations using lambda Expressions

Test tobj = new Test();
// Add two numbers using lambda expression
System.out.println("Addition is " + tobj.operate(5, 2, add));
// Multiply two numbers using lambda expression
System.out.println("Multiplication is " + tobj.operate(5, 2, multiply));
// lambda expression for single parameter
// This expression implements 'FuncInter2' interface
FuncInter2 fobj = message ->System.out.println("Hello " + message);
fobj.sayMessage("SynergyTop");
}
}

Output:

Addition is 7

Multiplication is 10

Hello SynergyTop

Important Points

  • The function_body of a Lambda expression can contain zero, one or more statements.
  • When there is a single statement curly brackets are not mandatory and the return type of the anonymous function is the same as that of the function_body expression.
  • When there are more than one statements, then these must be enclosed in curly brackets and the return type of the anonymous function is the same as the type of the value returned within the code block, or void if nothing is returned.

Java Lambda – Features

  • Java Lambda provides an optional declaration, therefore, we are not required to declare the parameter type.
  • It provides optional parenthesis around the parameter, thereby, bypassing the need to declare a single parameter in parenthesis. Parentheses are required only for multiple parameters.
  • Provides optional curly braces − we don’t need to use curly braces in expression body if the body contains a single statement.
  • Provide optional return keyword − the compiler automatically returns the value if the body has a single expression to return the value. Curly braces are required to indicate that expression returns a value

Our Verdict

Java Lambda helps in enhancing your application performance and offers a better user experience as compilation is not required in lambda.

We recommend that you continue to use Java Lambda instead of having certain static blocks and methods and writing long and object methods.

Reach out

Are you looking to develop a custom application solution in Java using Lambda? We can help! Write to contact@synergytop.com for a free quote.