Massachusetts Institute of Technology: Dr. George Kocur's "Introduction to Computing and Engineering Problem Solving: Methods and Scope"
Review these lecture notes.
A method must have a name but may not have parameters and a return type. Pages 1 - 2 explain how a method is declared in Java.
The parameter list contains variables that receive values from the caller. These variables are local to the method. Method parameters are also referred to as 'arguments' when they are substituted with specific values during the method call. Method parameters are explained on page 2.
Some methods do not return any value, while others return a value of certain data type. A method that does not return a value uses the keyword 'void' in the method signature. Value returning methods are illustrated on page 2 and non-value returning methods are illustrated in the example on page 3.
The scope of a variable refers to where the value of the variable is accessible or valid. A variable declared inside a method is only available in that method. The values of variables declared as parameters of a method are valid only inside that method as well. Read pages 4, 5, and 6 to learn about the scope of a variable.