Java Notes

Methods - Vocabulary

access modifier

There may be an access modifier at the front of a method header. The access modifier tells which other methods can call this method.

keyword	access
none	If you don't give an access modifier, every other method in this package can call it. This is usually called package access and is probably the most common type of access. This is like giving your friends your telephone number.
public	Everyone can call it. You should use public if you want someone outside your package to call the method. Some common methods that are declared public are paint(), init(), actionPerformed(), adjustmentValueChanged(), and main(). This is like making your phone number public -- anyone can call you.
private	No one outside this class can call it. This is like only letting your family call you.
protected	Everyone in this package and any child classes can use it. You won't want to use this unless you are devoloping classes that you expect others to use for inheritance.

actual parameter

The values in the method call are the actual parameters. When a call is made, the values of the actual parameters are copied into the formal parameters.

formal parameter

The parameters in the header of a method definition are the formal parameters. Formal parameters are like local variables that get their values from the actual parameters.

local variable

Local variables are variables that are declared in a method. Local variables can only be used in that method (no other methods can access them). They are created when a method is called, and destroyed when the method returns.

method

A method is a way to put a group of statements together to do something.

method body

Amethod body is the part of the method that contains the declarations of local variables and the statements. For a non-void function, it must contain at least one return statement.

method definition

A method definition has two parts: a method header, and a method body.

method header

A method header comes at the beginning and gives the following information:

• access modifier
• return type
• [an error occurred while processing this directive] method name
• formal parameters

Need to add: return type, return statement, signature, static/class methods, instance methods, overriding, overloading, ... However, each entry should really be marked both by area (methods, awt, ...), and by level (beginning, intermediate, or advanced). Hmmm, that will have to come later.