Quick demo playing with Java 8 streams, lambdas, and aggregate operations.

Java8Demo.java

import java.util.List;
import java.util.ArrayList;
import java.util.stream.*;
import java.util.Comparator;
import java.util.Collections;
import java.util.Optional;
import java.util.Random;

class Java8Demo {
    private static final String[] poolOfFirstNames = { "Joe", "Paul", "John", "Samantha", "Amanda", "Karen" };
    private static final String[] poolOfLastNames = {"Smith", "Lee", "Patel", "Hernandez"};

    public static void main(String[] args){
        List<Person> people = Stream.of(1, 2, 3, 4, 5)
                                    .parallel()
                                    .map(i -> new Person(getRandomFirstName(), getRandomLastName(), new Random().nextInt(100)))
                                    .collect(Collectors.toList());

        System.out.println("People: ");
        people.forEach(p -> System.out.println("\t" + p));

        System.out.println();

        System.out.println("People between the age of 20 and 40, sorted by Lastname, then by Firstname, then by age: ");
        people.stream()
            .parallel()
            .filter(person -> (person.getAge() >= 20 && person.getAge() <= 40))
            .sequential()
            .sorted(
                    Comparator.comparing(Person::getLastName)
                                .thenComparing(Person::getFirstName)
                                .thenComparing(Person::getAge)
            )
            .forEach(person -> System.out.println("\t" + person));

        System.out.println();

        Person oldestPerson = Collections.max(people, Comparator.comparing(Person::getAge));
        System.out.println("The oldest person is " + oldestPerson);

        String longestName = people.stream()
            .map(person -> person.getFirstName() + " " + person.getLastName())
            .collect(Collectors.maxBy(Comparator.comparing(String::length)))
            .orElse("Unknown");

        System.out.println("The longest full name in this list is '" + longestName + "'");

        System.out.println();

        boolean everyoneIsAlive = people.stream().allMatch(Person::isAlive);
        if (everyoneIsAlive) { 
            System.out.println("Yay, everyone is alive!");
        } else {
            System.out.println("Oh no, some of these people are dead! :(");
            people.stream()
                .filter(person -> !(person.isAlive()))
                .forEach(person -> System.out.println("\t" + person + " is dead. RIP " + person.getFirstName() + ". :("));
        }

    }

    public static class Person {
        private String firstName,
                       lastName;
        private Integer age;
        private boolean alive;

        public Person(String firstName, String lastName, int age){
            this.firstName = firstName;
            this.lastName = lastName;
            this.age = age;
            this.alive = (Math.random() < 0.5); // 50% chance of being either alive or dead
        }

        public String getFirstName(){ return this.firstName;    }
        public String getLastName() { return this.lastName;     }
        public Integer getAge()     { return this.age;          }
        public Boolean isAlive()    { return this.alive;        }

        public String toString() { return this.getFirstName() + " " + this.getLastName() + ", age " + this.getAge(); }
    }

    private static String getRandomFirstName()  { return poolOfFirstNames[new Random().nextInt(poolOfFirstNames.length)];   }
    private static String getRandomLastName()   { return poolOfLastNames[new Random().nextInt(poolOfLastNames.length)];     }
}