Main.java Source code

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Here is the source code for Main.java

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import java.time.LocalDate;
import java.time.chrono.IsoChronology;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Person> roster = createRoster();

        Integer totalAge = roster.stream().mapToInt(Person::getAge).sum();

        System.out.println("Sum of ages (sum operation): " + totalAge);

    }

    public static List<Person> createRoster() {

        List<Person> roster = new ArrayList<>();
        roster.add(
                new Person("Fred", IsoChronology.INSTANCE.date(1980, 6, 20), Person.Sex.MALE, "fred@example.com"));
        roster.add(new Person("Jane", IsoChronology.INSTANCE.date(1990, 7, 15), Person.Sex.FEMALE,
                "jane@example.com"));
        roster.add(new Person("George", IsoChronology.INSTANCE.date(1991, 8, 13), Person.Sex.MALE,
                "george@example.com"));
        roster.add(new Person("Bob", IsoChronology.INSTANCE.date(2000, 9, 12), Person.Sex.MALE, "bob@example.com"));

        return roster;
    }
}

class Person {

    public enum Sex {
        MALE, FEMALE
    }

    String name;
    LocalDate birthday;
    Sex gender;
    String emailAddress;

    Person(String nameArg, LocalDate birthdayArg, Sex genderArg, String emailArg) {
        name = nameArg;
        birthday = birthdayArg;
        gender = genderArg;
        emailAddress = emailArg;
    }

    public int getAge() {
        return birthday.until(IsoChronology.INSTANCE.dateNow()).getYears();
    }

    public void printPerson() {
        System.out.println(name + ", " + this.getAge());
    }

    public Sex getGender() {
        return gender;
    }

    public String getName() {
        return name;
    }

    public String getEmailAddress() {
        return emailAddress;
    }

    public LocalDate getBirthday() {
        return birthday;
    }

    public static int compareByAge(Person a, Person b) {
        return a.birthday.compareTo(b.birthday);
    }

}

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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 */