Pizza order example

I think it really depends on the application. If order application has checkboxes it makes more sense to use array. But if there is a textbox that you can type your toppings and split by comma, using string will be ok. In addition, If I am not wrong, string data type requires less memory space than array does. So you can carry toppings data as string toppings = "olive, onion, corn";

Firstly the example is used to demonstrate the use of methods (section of code that is called upon by the instantiated object of the class). So in that case it makes prefect sense.

Now to answer your question.

Consider using array in this case now
If I have a pizza store that offers say 5 pizza topping options. Then I would gladly use arrays

String [] pizzaToppings ={"Topping 1", "Topping 2", "Topping 3", "Topping 4", "Topping 5"}; 

Now let me consider a situation where I am big shot pizza guy and offer close to 60 toppings. So that would mean creating 60 indexes to store the pizza toppings in the array. This causes unnecessary memory usage for not all 60 toppings will be used at a go.

In this case methods seem more appropriate

public Pizza oderPizza (String toppings1){ };
//If I hypothetically call this method from somewhere like this 
class someClass{
order(){ pizza.orderPizza("Pineapple") }
}

Hope that explains. Ask again if you have doubts.