Simple Example

import java.util.*;
import java.lang.*;

public class PersonExecutor {
    public static void main( String[] arguments ){
        Person john = new Person();
        Person mike = new Person();
        
        john.setName( "John" );
        mike.setName( "Mike" );
        
        Location location = new Location();
        location.addPerson( john );
        location.addPerson( mike );
        
        System.out.print( location.toString() );
    }
}

class Person {
    private String name;
    public void setName( String name ) {
        this.name = name;
    }
    public String getName() {
        return name;
    }
}

class Location {
    private List<Person> persons = new ArrayList<Person>();
    public void addPerson( Person person ) {
        persons.add( person );
    }
    @Override
    public String toString() {
        String result = "";
        for ( Person person : persons ) {
            result += person.getName() + " is here\n";
        }
        return result;
    }
}