USER-DEFINED METHODS - Java Programming: From Problem Analysis to Program Design - page 428

If a method's name is overloaded, then all the methods (with the same name) have
different signatures if they have different formal parameter lists. Thus, the following
method headings correctly overload the method methodXYZ :
public void methodXYZ()
public void methodXYZ( int x, double y)
public void methodXYZ( double one, int y)
public void methodXYZ( int x, double y, char ch)
Consider the following method headings to overload the method methodABC :
public void methodABC( int x, double y)
public int methodABC( int x, double y)
Both method headings have the same name and same formal parameter list. Therefore,
these method headings to overload the method methodABC are incorrect. In this case, the
compiler will generate a syntax error. (Note that the return types of these method
headings are different.)
If a method's name is overloaded, then in a call to that method, the formal parameter list
of the method determines which method to execute.
Some authors define the signature of a method as the formal parameter list; other authors
consider the entire heading of the method as its signature. In this topic, the signature of a
method consists of the method's name and its formal parameter list. If the method names
are different, then, of course, the compiler would have no problem identifying which
method is called and correctly translating the code. However, if a method name is
overloaded, then, as noted, the method's formal parameter list determines which
method's body executes.
Suppose you need to write a method that determines the larger of two items. Both items
can be integers, floating-point numbers, characters, or strings. You could write several
methods as follows (we give only the method heading):
int largerInt( int x, int y)
char largerChar( char first, char second)
double largerDouble( double u, double v)
String largerString(String first, String second)
The method largerInt determines the larger of two integers, the method largerChar
determines the larger of two characters, and so on. All of these methods perform similar
operations. Instead of giving different names to these methods, you can use the same name—
say, larger —for each method; that is, you can overload the method larger as follows:
int larger( int x, int y)
char larger( char first, char second)
double larger( double u, double v)
String larger(String first, String second)