Methods:

Methods are also called functions or subroutines. All three names are synonymous.

what? Pieces of code that are in a code block that does a specific function

why?

to split up code into logical blocks. You should probably never have more than 100 lines of code in one method.
so that you can reuse the same useful code in many places
we extend both of these ideas when we look at objects.

Syntax:

[modifiers]  [return value] [function name]  ( [arguments] ) {
	[statements]
}

Example:

static int square(int x) {
	return x*x;
}

This method is called square. It takes one number that is an int. It returns an int. For now, we'll just ignore the modifiers. The most common ones are private, public, and static.

Naming methods:

1. must start with lowercase (use camelCase)
2. recommended to start with a verb. e.g. getInput()

Calling methods

use the name of the method
use the correct number and type of parameters
if you want to, use the return value for something.

double x = Math.sin(Math.PI/3); 
System.out.print("stuff");

Parameters

Note that the parameters in a method header are local variables. This means that their names have no relation to any other variable name in the program. (See the section on scope of variables **insert link**)
The variables are created in the method header and they are destroyed when the final } ends the method

The critical thing about parameters is their order and type

Have a look at the program below. (To run it you'd have to make both methods static)

void method1() {
	String fruit = "cherry";
	String store = "The Bay";
	int favNumber = 20161024;
	
	method2(store, fruit, favNumber); //we don't have to do anything with the boolean that is returned
	boolean result = method2("Mr. Smith", store, myStaticInt);
	if (result) System.out.println("oops. Bye \"" + store + "\"");
	
}

boolean method2(String assassin, String target, int date) {
	
	boolean success;  //ERROR: local variables MUST be initialized.
	
	success = false;
	System.out.println("The target is " + target);
	if (assassin.equals("Mr. Smith")) success=true;
	return success;
}