package basic.lambda; public class Feature { // 可选类型声明 - 无需声明参数的类型。编译器可以从该参数的值推断。 // 可选圆括号参数 - 无需在括号中声明参数。对于多个参数，括号是必需的。 // 可选大括号 - 表达式主体没有必要使用大括号，如果主体中含有一个单独的语句。 // 可选return关键字 - 编译器会自动返回值，如果主体有一个表达式返回的值。花括号是必需的，以表明表达式返回一个值。 public static void main(String[] args) { Feature ft = new Feature(); // with type declaration MathOperation addition = (int a, int b) -> a + b; // with out type declaration MathOperation subtraction = (a, b) -> a - b; // with return statement along with curly braces MathOperation multiplication = (int a, int b) -> { return a * b; }; // without return statement and without curly braces MathOperation division = (int a, int b) -> a / b; System.out.println("10 + 5 = " + ft.operate(10, 5, addition)); System.out.println("10 - 5 = " + ft.operate(10, 5, subtraction)); System.out.println("10 x 5 = " + ft.operate(10, 5, multiplication)); System.out.println("10 / 5 = " + ft.operate(10, 5, division)); // with parenthesis GreetingService greetService1 = message -> System.out.println("Hello " + message); // without parenthesis GreetingService greetService2 = (message) -> System.out .println("Hello " + message); greetService1.sayMessage("Mahesh"); greetService2.sayMessage("Suresh"); } interface MathOperation { int operation(int a, int b); } interface GreetingService { void sayMessage(String message); } private int operate(int a, int b, MathOperation mathOperation) { return mathOperation.operation(a, b); } }