CLASSES

Examples of Method Declarations

8.4.8

either they have different return types or one has a return type and the other

is

void

. Moreover, a compile time error occurs if the inherited method that

is not

abstract

 has a

throws

 clause that conflicts ( 8.4.4) with that of any

other of the inherited methods.

If none of the inherited methods is not

abstract

, then the class is necessarily

an

abstract

 class and is considered to inherit all the

abstract

 methods. A

compile time error occurs if, for any two such inherited methods, either they

have different return types or one has a return type and the other is

void

. (The

throws

 clauses do not cause errors in this case.)

It is not possible for two or more inherited methods with the same signature not to

be

abstract

, because methods that are not

abstract

 are inherited only from the

direct superclass, not from superinterfaces.

There might be several paths by which the same method declaration might be

inherited from an interface. This fact causes no difficulty and never, of itself,

results in a compile time error.

8.4.7   Overloading

If two methods of a class (whether both declared in the same class, or both inher 

ited by a class, or one declared and one inherited) have the same name but differ 

ent signatures, then the method name is said to be

overloaded

. This fact causes no

difficulty and never of itself results in a compile time error. There is no required

relationship between the return types or between the

throws

 clauses of two meth 

ods with the same name but different signatures.

Methods are overridden on a signature by signature basis. If, for example, a

class declares two

public

 methods with the same name, and a subclass overrides

one of them, the subclass still inherits the other method. In this respect, Java dif 

fers from C++.

When a method is invoked ( 15.11), the number of actual arguments and the

compile time types of the arguments are used, at compile time, to determine the

signature of the method that will be invoked ( 15.11.2). If the method that is to be

invoked is an instance method, the actual method to be invoked will be determined

at run time, using dynamic method lookup ( 15.11.4).

8.4.8   Examples of Method Declarations

The following examples illustrate some (possibly subtle) points about method

declarations.

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