Modern programming languages are very small, but they allow you to extend the language by creating new command words.
In Java, a new word is called a function or method. Functions are a powerful way to keep your code readable and easy to maintain.
A function is an abstraction: it does something, but you don't have to know how it does it in order to use it.
You can think of a function as a machine. All machines have some function (do something):

• Some machines (like a meat grinder) require input of raw materials and output (return) processed materials.
• Other machines (like a music box) produce output (music) without any specific input.
• Still other machines have neither inputs nor outputs but affect other things (like pressing the button on your car remote control)

Every Java function has 4 primary characteristics:

• a name followed by parentheses
• optional inputs (called parameters) placed inside the parentheses
• a body (the code that defines what the function does)
• an optional output (called a return value)

Consider the following function:

   int square(int a) {
       return a * a;
   }

The function's name is 'square' and it takes an input parameter that is an integer and is referred to within the function as a. The function returns an integer that it computes by multiplying a by itself.

Functions can take more than one parameter, but they can only return 1 value (or no values). Consider this function that takes two input parameters and returns no value:

   void echo(String msg, int times) {
        for (int n=0; n<times; n++) {
            System.out.println(msg);
        }
   }

Create a new EchoExample? project folder and in it create an Echo program as follows:

public class Echo {

    static void echo(String msg, int times) {
        for (int n=0; n<times; n++) {
            System.out.println(msg);
        }
   }
    public static void main(String args[]) {
        echo("howdy", 10);
    }
}

• Run the program and observe the output
• For now, we're going to ignore the keywords public and static, we'll get to those soon