Cookbooks
Java
Chapter 5. Good Coding Practices
Organizing code into functions

Java:
Organizing code into functions

How to:

Here’s a classic example — a function to calculate the factorial of a number.

public class MathUtils {

    public static void main(String[] args) {
        int number = 5;
        int result = factorial(number);
        System.out.println("Factorial of " + number + " is: " + result);
    }
    
    public static int factorial(int n) {
        if (n <= 1) {
            return 1;
        }
        return n * factorial(n - 1);
    }
}

Output would be:

Factorial of 5 is: 120

Deep Dive

Before functions were a thing, code was crammed into monolithic blocks, making debugging like finding a needle in a haystack. Now, encapsulating functionality into functions helps isolate issues fast. Alternatives include lambda expressions in Java or methods in object-oriented programming, both serving similar purposes. When you write a function, remember: (1) Each function should have a single responsibility and (2) the name of the function should clearly describe its purpose.

See Also

For more on organizing code:

LoggingRefactoring