BSc IT - Structure Programming Methodology - Java

A user-defined function in Java is a block of code that you, the programmer, write to perform a specific task. Unlike built-in functions (like `System.out.println()`), user-defined functions are created by you and can be used again and again in your program. You define them using a name, a return type, and optionally parameters.

Example:

public class MyProgram {
    // User-defined function
    public static void greet() {
        System.out.println("Hello, welcome to Java!");
    }

    public static void main(String[] args) {
        greet();  // Calling the user-defined function
    }
}

In this example, `greet()` is a user-defined function that prints a message. We call it inside the `main` method to use its functionality. This helps avoid repeating code and makes your program organized and easier to manage.