ojitha

import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;

interface Functor<T, F extends Functor<?,?>> {
    <R> F map (Function<T, R> f);
}
class FList<T> implements Functor<T, FList<?>> {

    private final List<T> list;

ojitha

import java.math.BigInteger;
import java.util.Arrays;

import java.util.stream.IntStream;
//var r =IntStream.rangeClosed(1,5)
//        .reduce(1,(x,y) -> x * y);
//        //.forEach(System.out::println);

static BigInteger factorial(int n){
    return IntStream.rangeClosed(1, n)

ojitha

import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Stream;

@FunctionalInterface
interface ExFunction<E, F> {
    F apply (E e) throws Throwable;
    static <E, F> Function<E, Optional<F>> wrap (ExFunction<E, F> op){

ojitha

/*
    This example shows how to group employees by their departments.
    The intention of this example, to show the use of the <b>Collectors.groupingBy</b>
    functionality.

 */
import java.util.List;
import java.util.stream.Collectors;

class Dept {