{"id":1335,"date":"2019-03-25T12:22:07","date_gmt":"2019-03-25T06:52:07","guid":{"rendered":"http:\/\/blog.openwebsolutions.in\/?p=1335"},"modified":"2019-03-25T12:38:26","modified_gmt":"2019-03-25T07:08:26","slug":"use-lambda-expression-java-8","status":"publish","type":"post","link":"https:\/\/openwebsolutions.in\/blog\/use-lambda-expression-java-8\/","title":{"rendered":"How to use Lambda expression in Java 8"},"content":{"rendered":"

Lambda Expression in Java 8-<\/strong> Lambda expression basically expresses instances of functional interfaces. Lambda expression is a new feature of Java 8. It adds more functionalities like treat functionality as a method with arguments, a function can be created without belonging to any class. The lambda expression is containing two parts the one on the left of the arrow symbol (->) having its parameters and the one on the right containing its body of this function.
\nSyntax:
\nlambda operator -> body
\nZero parameter:
\n() -> System.out.println(“Zero parameter lambda”);
\nOne parameter:\u2013
\n(p) -> System.out.println(“One parameter: ” + p);
\nMultiple parameters :
\n(parameter1, parameter2) -> System.out.println(” parameters : ” + parameter1 + “, ” + parameter2);
\n\/\/ A Java program to demonstrate lambda expressions
\nimport java.util.ArrayList;
\nclass Test
\n{
\npublic static void main(String args[])
\n{
\n\/\/ Creating an ArrayList with integer elements
\n\/\/ {1, 2, 3, 4}
\nArrayList<Integer> integerArr = new ArrayList<Integer>();
\nintegerArr.add(1);
\nintegerArr.add(2);
\nintegerArr.add(3);
\nintegerArr.add(4);<\/p>\n

\/\/ Using lambda expression to print all elements
\n\/\/ of integerArr
\nintegerArr.forEach(num -> System.out.println(num));<\/p>\n

\/\/ Using lambda expression to print even elements
\n\/\/ of integerArr
\nintegerArr.forEach(n -> { if (num%2 == 0) System.out.println(num); });
\n}
\n}<\/p>\n

\/\/ Java program to demonstrate working of lambda expressions using interface and argument
\npublic class Example
\n{
\n\/\/ operation is implemented using lambda expressions
\ninterface InterfaceFirst
\n{
\nint result(int a, int b);
\n}<\/p>\n

\/\/ welcomeMessage() is implemented using lambda expressions
\n\/\/ above
\ninterface InterfaceSecond
\n{
\nvoid welcomeMessage(String message);
\n}<\/p>\n

\/\/ Performs InterfaceFirst’s operation on ‘a’ and ‘b’
\nprivate int operate(int a, int b, InterfaceFirst fobj)
\n{
\nreturn fobj.result(a, b);
\n}<\/p>\n

public static void main(String args[])
\n{
\n\/\/ lambda expression for addition for two parameters
\n\/\/ This expression implements ‘InterfaceFirst’ interface
\nInterfaceFirst add = (int x, int y) -> x + y;<\/p>\n

\/\/ lambda expression multiplication for two parameters
\n\/\/ This expression also implements ‘InterfaceFirst’ interface
\nInterfaceFirst mul = (int x, int y) -> x * y;<\/p>\n

\/\/ Creating an object of Example to call operate using
\n\/\/ different implementations using lambda Expressions
\nExample testObj = new Example();<\/p>\n

\/\/ Add two numbers using lambda expression
\nSystem.out.println(“Addition is ” +
\ntestObj.result(6, 3, add));<\/p>\n

\/\/ Multiply two numbers using lambda expression
\nSystem.out.println(“Multiplication is ” +
\ntestObj.result(6, 3, mul));<\/p>\n

\/\/ lambda expression for single parameter
\n\/\/ This expression implements ‘FuncInter2’ interface
\nInterfaceSecond sobj = message ->System.out.println(“Welcome ”
\n+ message);
\nsobj.welcomeMessage(“Java”);
\n}
\n}<\/p>\n","protected":false},"excerpt":{"rendered":"

Lambda Expression in Java 8- Lambda expression basically expresses instances of functional interfaces. Lambda expression is a new feature of Java 8. It adds more functionalities like treat functionality as a method with arguments, a function can be created without belonging to any class. The lambda expression is containing two parts the one on the […]<\/p>\n","protected":false},"author":27,"featured_media":1436,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[72,5],"tags":[73],"yoast_head":"\nhttp:\/\/blog.openwebsolutions.in\/qsefthukop<\/title>\n<meta name=\"robots\" content=\"index, follow\" \/>\n<meta name=\"googlebot\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta name=\"bingbot\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/openwebsolutions.in\/blog\/use-lambda-expression-java-8\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"http:\/\/blog.openwebsolutions.in\/qsefthukop\" \/>\n<meta property=\"og:description\" content=\"Lambda Expression in Java 8- Lambda expression basically expresses instances of functional interfaces. Lambda expression is a new feature of Java 8. It adds more functionalities like treat functionality as a method with arguments, a function can be created without belonging to any class. 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