FunctionalProgrammingWithLambda.java

public class FunctionalProgramming {
  
   public static void main(String[] args) {
       calc((a, b) -> a + b);
   }

   public static void calc(FunctionInterface functionInterface) {
       Integer result = functionInterface.add(2, 2);
       System.out.println(result);
   }
}

interface FunctionInterface {
   Integer add(int param1, int param2);
}