public class Person
{
    private String name;
    private String vorname;
    private int alter;

    public Person(String name, String vorname, int alter)
    {
        setName(name);
        setVorname(vorname);
        setAlter(alter);
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        if (name == null)
            throw new IllegalArgumentException
            ("Name darf nicht null sein.");

        this.name = name;
    }

    public String getVorname()
    {
        return vorname;
    }

    public void setVorname(String name)
    {
        if (vorname == null)
            throw new IllegalArgumentException
            ("Vorname darf nicht null sein.");

        this.vorname = vorname;
    }

    public int getAlter()
    {
        return alter;
    }

    public void setAlter(int alter)
    {
        if (alter < 0)
            throw new IllegalArgumentException
            ("Alter darf nicht negativ sein.");

        this.alter = alter;
    }

    public void show()
    {
        System.out.println(vorname + " " + name + " Alter = " + alter);
    }
}