object is constructed it may exhibit different behavior.

First lets create an interface named Item which contains the two public methods one for packaging the item and other for defining the price of each item.

We are putting all the classes in the package builder.

package builder;

public interface Item {

public Packing pack();

public int price();

}

Lets consider this class as Pizza.java:

package builder;
public abstract class Pizza implements
Item {
public Packing pack() {
return new Wrapper();
}
public abstract int price();
}

Now the class pizza further extended to Italianpizza, Cheesepizza etc. All these classes will implement the price() method and return a price for each type of pizza. In this example we are implementing the Italianpizza class of the Pizza class.

Italianpizza.java

package builder;
public class Italianpizza extends Pizza
{
public int price() {
return 200;
}
}

Now lets consider the item Ice Cream

IceCream.java
package builder;
public class IceCream
implements Item {
public Packing pack() {
return new Envelop();
}
public int price() {
return 20;
}}

package builder;
public class MealBuilder {
public Packing additems() {
Item[] items = {new Italianpizza(),
new IceCream(), new Coke()}
return new MealBox().
addItems(items);
}