USER-DEFINED METHODS - Java Programming: From Problem Analysis to Program Design - page 444

18 . When a program executes, the execution always begins with the first
statement in the method main .
19 . User-defined methods execute only when they are called.
20 . A call to a method transfers control from the caller to the called method.
21 . In a method call statement, you specify only the actual parameters, not their
data type or the method type.
22 . When a method exits, control goes back to the caller.
23 . A method that does not have a return data type is called a void method.
24 . A return statement without any value can be used in a void method.
25 . If a return statement is used in a void method, it is typically used to exit the
method early.
26 . In Java, void is a reserved word.
27 . A void method may or may not have parameters.
28 . To call a void method, you use the method name together with the actual
parameters in a stand-alone statement.
29 . A formal parameter receives a copy of its corresponding actual parameter.
30 . If a formal parameter is of the primitive data type, it directly stores the value
of the actual parameter.
31 . If a formal parameter is a reference variable, it copies the value of its
correspondingactualparameter,whichistheaddressoftheobject
where the actual data is stored. Therefore, if a formal parameter is a
reference variable, both the formal and actual parameters refer to the
same object.
32 . The scope of an identifier refers to those parts of the program where it is
accessible.
33 . Java does not allow the nesting of methods. That is, you cannot include the
definition of one method in the body of another method.
34 . Within a method or a block, an identifier must be declared before it can be
used. Note that a block is a set of statements enclosed within braces. A
method's definition can contain several blocks. The body of a loop or an if
statement also forms a block.
35 . Within a class, outside every method definition (and every block), an
identifier can be declared anywhere.
36 . Within a method, an identifier used to name a variable in the outer block of
the method cannot be used to name any other variable in an inner block of
the method.
37 . The scope rules of an identifier declared within a class and accessed within a
method (block) of the class are as follows: