How do I create an object(function)?

I am new to java, but have taken one VB class.
I am working on a common exercise:
Bags of coffee sell for $5.50.
User orders a number of bags.
number of bags * cost per bag.
Bags are shipped in 3 sizes of boxes: large, medium, and small.
Cost: Large= $ 1.80, Medium cost $1.00, and Small cost $0.60.
The goal is to minimize cost- pack the bags most efficiently and cheaply.
I have worked up to the equation: number of bags * cost per bag.
I don't know how to create a function in java to do the other computing.

If you don't know this, I suggest you start at the beginning:
Java Tutorials
In particular:
Defining Methods

I guess I was not clear:

Class object;
object = new Class;

What I meant was I wasn't clear how to word the function that computed
the amount of boxes needed.

Thank you for posting the links. They do explain what I need to do.

I suggest looking at how to define classes.

Code Java:

---

public class Box
{
    // your class definition goes here
 
    // this is a field
    private int fitsHowManyCoffees;
 
    // this is a constructor
    public Box(int fitsHowManyCoffees)
    {
        this.fitsHowManyCoffees = fitsHowManyCoffees;
    }
 
    // this is a method
    public int getFitsHowMany()
    {
        return fitsHowManyCoffees;
    }
}

---

Code Java:

---

public class User
{
    public static void main(String[] args)
    {
        // this creates a new box which can hold 3 coffees
        Box holds3 = new Box(3);
        System.out.println("the box holds " + holds3.getFitsHowMany() + " coffees.");
    }
}

---