theboreddev

        final Item item = new Item(1L, new BigDecimal("12.99"));
        System.out.println("Delivery price is " + Plan.BASIC.deliveryPrice.apply(item));
        System.out.println("Delivery price is " + Plan.PREMIUM.deliveryPrice.apply(item));
        System.out.println("Delivery price is " + Plan.BUSINESS.deliveryPrice.apply(item));

theboreddev

        final Car car = new Car();

        final CarWashStep chain = new InitialWashStep();

        chain.andThen(new SoapStep())
                .andThen(new RinseStep())
                .andThen(new PolishStep())
                .andThen(new DryStep());

        final Car finalCar = chain.applyTo(car);

theboreddev

package com.theboreddev.examples.forkjoin;

import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

public class ForkJoinExample {

    public static void main(String[] args) {

theboreddev

        final Collection<Employee> employees = List.of(
                new Employee("Karen Smith", 51200.0, 29, Employee.Sex.FEMALE),
                new Employee("John Smith", 24000.0, 32, Employee.Sex.MALE),
                new Employee("Anthony Jackson", 44000.0, 33, Employee.Sex.MALE),
                new Employee("Alyson Palmer", 34320.0, 36, Employee.Sex.FEMALE),
                new Employee("Jessica Sanders", 64320.0, 34, Employee.Sex.FEMALE)
        );

        final Map<Employee.Sex, List<Employee>> employeesBySex = employees.stream()
                .collect(groupingBy(Employee::getSex));

theboreddev

        final Map<Employee.Sex, Set<Employee>> employeesBySex = employees.stream()
                .collect(groupingBy(Employee::getSex, toSet()));

theboreddev

        final Map<Employee.Sex, Double> averageAgeBySex = employees.stream()
                .collect(groupingBy(Employee::getSex, averagingInt(Employee::getAge)));

theboreddev

        final Map<Employee.Sex, Map<Integer, List<Employee>>> groupBySexAndAge = employees.stream()
                .collect(groupingBy(Employee::getSex, groupingBy(Employee::getAge)));

theboreddev

        final Map<Employee.Sex, Optional<Employee>> youngestEmployeeBySex = employees.stream()
                .collect(groupingBy(Employee::getSex, minBy(comparing(Employee::getAge))));

theboreddev

        final Map<Employee.Sex, List<Employee>> employeesOverThirtyBySex = employees.stream()
                .collect(groupingBy(Employee::getSex, filtering(employee -> employee.getAge() > 30, toList())));

theboreddev

        final Collection<Employee> employees = List.of(
                new Employee("Karen Smith", 51200.0, 29, Employee.Sex.FEMALE),
                new Employee("John Smith", 24000.0, 32, Employee.Sex.MALE),
                new Employee("Anthony Jackson", 44000.0, 33, Employee.Sex.MALE),
                new Employee("Alyson Palmer", 34320.0, 36, Employee.Sex.FEMALE),
                new Employee("Jessica Sanders", 64320.0, 34, Employee.Sex.FEMALE)
        );

        final Map<Employee.Sex, List<Employee>> existingMap = new HashMap<>() {
            {