Main.java Source code

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Here is the source code for Main.java

Source

import java.time.LocalDate;
import java.time.Month;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        Map<Gender, Map<Object, String>> personsByGenderAndDobMonth = Employee.persons().stream().collect(
                Collectors.groupingBy(Employee::getGender, Collectors.groupingBy(p -> p.getDob().getMonth(),
                        Collectors.mapping(Employee::getName, Collectors.joining(", ")))));

        System.out.println(personsByGenderAndDobMonth);
    }
}

enum Gender {
    MALE, FEMALE
}

class Employee {
    private long id;
    private String name;
    private Gender gender;
    private LocalDate dob;
    private double income;

    public Employee(long id, String name, Gender gender, LocalDate dob, double income) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.dob = dob;
        this.income = income;
    }

    public String getName() {
        return name;
    }

    public Gender getGender() {
        return gender;
    }

    public LocalDate getDob() {
        return dob;
    }

    public static List<Employee> persons() {
        Employee ken = new Employee(1, "Jame", Gender.MALE, LocalDate.of(1970, Month.MAY, 4), 6123.0);
        Employee jeff = new Employee(2, "Jeff", Gender.MALE, LocalDate.of(1971, Month.JULY, 5), 7112.0);
        Employee donna = new Employee(3, "Jane", Gender.FEMALE, LocalDate.of(1972, Month.JULY, 9), 8712.0);
        Employee chris = new Employee(4, "Jodd", Gender.MALE, LocalDate.of(1973, Month.DECEMBER, 6), 1823.0);
        Employee laynie = new Employee(5, "Janey", Gender.FEMALE, LocalDate.of(1974, Month.DECEMBER, 3), 1234.0);
        Employee lee = new Employee(6, "Jason", Gender.MALE, LocalDate.of(1975, Month.MAY, 8), 2412.0);

        // Create a list of persons
        List<Employee> persons = Arrays.asList(ken, jeff, donna, chris, laynie, lee);

        return persons;
    }
}