public class FunctionPointerDemo {

        public static void main(String[] args) {

                // bigger than implementation
                FunctionPointer fp = new FunctionPointer() {
                        public String function(int a, int b) {
                                if (a > b)
                                        return "bigger";
                                else
                                        return "not bigger";
                        }
                };
                comparison(1, 2, fp);
                comparison(3, 2, fp);

                // smaller than implementation
                FunctionPointer fp2 = new FunctionPointer() {
                        public String function(int a, int b) {
                                if (a < b)
                                        return "smaller";
                                else
                                        return "not smaller";
                        }
                };
                comparison(1, 2, fp2);
                comparison(3, 2, fp2);
        }

        // prototype
        interface FunctionPointer {
                public String function(int a, int b);
        }

        // function with fp class as argument
        public static void comparison(int a, int b, FunctionPointer fp) {
                System.out.printf("%d is %12s than %d\n", a, fp.function(a, b), b);
        }
}