Java Uml Help

[Mxlfa]

Ok you guys are my last hope, i've tried searching what i need and i cant find it. i really tried searching.... but i just don't know exactly what i'm really searching for...
i have to do the following project in c# (wrong post haha) but if you could help out in java i could just "translate" it to c# really doesn't matter http://personal.cityu.edu.hk/~dcrosela/teaching/04-05/dco20105/lab/figures/lab1/soln-one-uml-gou-cof.jpg so if anyone could help i'm stuck on the order part where it has to get a product i have a catalogProdcts<Products> that hold products so im not sure if i have to point my order to catalogproduct and use my method get product to retrieve a certian product heres some code...

public class Catalog
    {

        private Generica<Product> lista;

        public Catalog() {
            lista = new Generica<Product>();
        }

        public void agregar(Product prod) {
            lista.add(prod);
        }

        public Product getProducto(int index) {
            return lista.get(index);
        }
        public Product getProducto(String codigo){
		
		foreach (Product p in lista ){
			if (p._code.Equals(codigo)){
				return p;
			}
		}
		return null;
	}


        public bool borrar(int index) {
            return lista.eliminar(index);
        }

        public void modificar(int index, Product prod) {
            lista.modifica(index, prod);
        }

        public int length() {
            return lista.Count;
        }

    }

public class Product 
    {
        private String code;
        private String description;
        private double price;

        public Product(String code, String description, double price)
        {
            this.code = code;
            this.description = description;
            this.price = price;
        }
        public String _code
        {
            get { return code; }
        }

        public String _description
        {
            get { return description; }
        }

        public double _price
        {
            get { return price; }
        }

        public int CompareTo(object obj)
        {
            if (obj is Product)
            {
                Product prod = (Product)obj;
                if (this.price < prod.price)
                {
                    return -1;
                }
                else
                {
                    if (this.price > prod.price)
                    {
                        return 1;
                    }
                    else
                    {
                        return 0;
                    }
                }
            }
            else
            {
                throw new System.InvalidCastException("Tipos no comparables");
            }
        }

        public int CompareTo(Product other)
        {
            if (other is Product)
            {
                Product prod = (Product)other;
                if (this.price < prod.price)
                {
                    return -1;
                }
                else
                {
                    if (this.price > prod.price)
                    {
                        return 1;
                    }
                    else
                    {
                        return 0;
                    }
                }
            }
            else
            {
                throw new System.InvalidCastException("Tipos no comparables");
            }
        }
    }

and what i have for orderItem

class OrderItem //: IComparable<OrderItem>
    {
        int _quantity;
        private Product _product;

        public OrderItem(int quantity)
        {
            this._quantity = quantity;
        }

        public int quantity
        {
            get { return quantity; }
            set { _quantity = value;  }
        }
        public Catalog getProducto(String codigo)
        {
            Catalog
            return c;
        }
        
    }

Help please!!!! (:

Your UML actually tells you the solution. Your engine GourmetCoffee has a catalog object with a list of Products. You can invoke getProduct(String) on your catalog to get an Product to add to an OrderItem which is added to an Order. The order is added to a Sales object.

I'd imagine your GourmetCoffee would do something like this:

Catalog catalog = new Catalog();
		
		Sales sale = new Sales();
		Order order = new Order();
		
		OrderItem item = new OrderItem();
		item.setProduct(catalog.get("FooBar Blend"));
		item.setQuantity(3);
		
		order.addItem(item);
		sale.addOrder(order);
		this.addSales(sale);