DateComparator.java

import java.util.Comparator;

public class DateComparator implements Comparator<Person> {
	public int compare (Person person, Person person1) {
		if (person.getRawBirthday ().after (person1.getRawBirthday ())) {
			return (1);
		}

		if (person.getRawBirthday ().before (person1.getRawBirthday ())) {
			return (-1);
		}

		return (person.compareTo (person1));
	}
}

FieldComparator.java

import java.text.Collator;
import java.util.Comparator;
import java.util.Locale;

public class FieldComparator implements Comparator<Person> {
	public int compare (Person person, Person person1) {
		Collator collator = Collator.getInstance (new Locale ("cs"));

		return (collator.compare (person.getField (), person1.getField ()));
	}
}

Main.java

import java.util.*;

public class Main {
	private static List<Person> list = new ArrayList<Person> ();

	public static void main (String[] args) {
		Main main = new Main ();
		main.fillArray ();
		main.printList (list);
		main.showSort ();
	}

	private void fillArray () {
		list.add (new Person ("Jan", "Novák", "běžec", "1. 1. 1990", 60.5, 1.75));
		list.add (new Person ("Pepa", "Vomáčka", "fotbalista", "5. 7. 1990", 65.5, 1.78));
		list.add (new Person ("Jan", "Hřebejk", "běžec", "1. 12. 1990", 55.5, 1.70));
		list.add (new Person ("Franta", "Král", "kriketista", "5. 10. 1990", 60., 2.30));
		list.add (new Person ("Jan", "Král", "basketbalista", "9. 11. 1990", 60.2, 2.25));
		list.add (new Person ("Jan", "Vorel", "floorballista", "10. 10. 1990", 70, 2.5));
		list.add (new Person ("Pepa", "Vorel", "floorballista", "10. 10. 1990", 70.5, 2.));
		list.add (new Person ("Pepa", "Skočdopole", "fotbalista", "10. 10. 1990", 70.5, 2.));
		list.add (new Person ("Pepa", "Nejezchleba", "fotbalista", "10. 10. 1990", 70.5, 2.));
		list.add (new Person ("Pepa", "Bezfantazie", "běžec", "10. 10. 1990", 70.5, 2.));
	}

	private void printList (List<Person> list) {
		for (Person person : list) {
			System.out.println (person.getFirstName () + " " + person.getLastName () + "; " +
					person.getBirthday () + ", " + person.getField () + ", " +
					person.getWeight () +"kg, " + person.getWidth () + "m.");
		}

		System.out.println ();
	}

	private void showSort () {
		Scanner scanner = new Scanner (System.in);
		String input;

		do {
			System.out.println ("Podle čeho řadit? 1 – jméno, 2 – obor, 3 – narození, 4 – váha, 5 – výška.");
			System.out.println ("9 pro otočení řazení.");
			System.out.println ("0 pro ukončení.");

			input = scanner.next ();

			if (!input.equals ("0")) {
				if (input.equals ("1")) {
					Collections.sort (list);
				} else if (input.equals ("2")) {
					Collections.sort (list, new FieldComparator ());
				} else if (input.equals ("3")) {
					Collections.sort (list, new DateComparator ());
				} else if (input.equals ("4")) {
					Collections.sort (list, new WeightComparator ());
				} else if (input.equals ("5")) {
					Collections.sort (list, new WidthComparator ());
				} else if (input.equals ("9")) {
					Collections.reverse (list);
				} else {
					System.out.println ("Neumíš číst nebo psát?");
				}

				printList (list);
			} else {
				break;
			}
		} while (true);
	}
}

Person.java

import java.text.Collator;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

public class Person implements Comparable<Person> {
	private String firstName;
	private String lastName;
	private String field;
	private Date birthday;
	private double weight;
	private double width;

	public Person (String firstName, String lastName, String field, String birthday, double weight, double width) {
		this.firstName = firstName;
		this.lastName = lastName;
		this.field = field;
        this.weight = weight;
		this.width = width;
		setBirthday (birthday);
	}

	public String getFirstName () {
		return firstName;
	}

	public void setFirstName (String firstName) {
		this.firstName = firstName;
	}

	public String getLastName () {
		return lastName;
	}

	public void setLastName (String lastName) {
		this.lastName = lastName;
	}

	public String getField () {
		return field;
	}

	public void setField (String field) {
		this.field = field;
	}

	public String getBirthday () {
		Calendar calendar = Calendar.getInstance ();
		StringBuilder stringBuilder = new StringBuilder ();
		String string;

		calendar.setTime (birthday);
		stringBuilder.append (calendar.get (Calendar.DAY_OF_MONTH)).append (". ");
		stringBuilder.append (calendar.get (Calendar.MONTH) + 1).append (". ");
		stringBuilder.append (calendar.get (Calendar.YEAR));

		string = stringBuilder.toString ();

		return string;
	}

	public Date getRawBirthday () {
		return (birthday);
	}

	public void setBirthday (String birthday) {
		DateFormat format = new SimpleDateFormat ("d. M. yyyy");

		try {
			this.birthday = format.parse (birthday);
		} catch (ParseException e) {
			System.out.println ("Špatný formát data!");
		}
	}

	public double getWeight () {
		return weight;
	}

	public void setWeight (double weight) {
		this.weight = weight;
	}

	public double getWidth () {
		return width;
	}

	public void setWidth (double width) {
		this.width = width;
	}

	public int compareTo (Person person) {
		Collator collator = Collator.getInstance (new Locale ("cs"));
		int result;

		result = collator.compare (lastName, person.getLastName ());

		if (result == 0) {
			result = collator.compare (firstName, person.getFirstName ());
		}

		return (result);
	}

	public String toString () {
		return (getFirstName () + " " + getLastName ());
	}
}

WeightComparator.java

import java.util.Comparator;

public class WeightComparator implements Comparator<Person> {
	public int compare (Person person, Person person1) {
		if (person.getWeight () > person1.getWeight ()) {
			return (1);
		}

		if (person.getWeight () < person1.getWeight ()) {
			return (-1);
		}

		return (0);
	}
}

WidthComparator.java

import java.util.Comparator;

public class WidthComparator implements Comparator<Person> {
	public int compare (Person person, Person person1) {
		if (person.getWidth () > person1.getWidth ()) {
			return (1);
		}

		if (person.getWidth () < person1.getWidth ()) {
			return (-1);
		}

		return (0);
	}
}