# The Fibonacci Example

As a base for the illustrations presented later in this chapter, we will use a simple utility class able to calculate fibonacci numbers.

The code of the class is:

```  public class Fibonacci{

public Fibonacci(){ }

public long get(int n){
if (n == 0 || n == 1){
return (long) n;
}

return get(n - 1) + get(n - 2);
}

public static void main(String[] args){
if (args.length == 0){
System.out.println("Please specify which fibonacci number
should be calculated.");
System.exit(0);
}

int theN = Integer.parseInt(args);

long theFibonacciNumber = new Fibonacci().get(theN);
System.out.println("The fibonacci[" + theN + "] is " + theFibonacciNumber);

System.out.println();

long theFibonacciNumberPlusOne = new Fibonacci().get(theN + 1);
System.out.println("The fibonacci[" + (theN + 1) + "] is " +
theFibonacciNumberPlusOne);
}
}```

This piece of code is pretty straightforward to read: there is one empty constructor to obtain Fibonacci objects references and one unique method to calculate a fibonacci number based on the parameter that represents the one we are interested on. 