6

C H A P T E R

Names

The Tao that can be told is not the eternal Tao;

The name that can be named is not the eternal name.

The Nameless is the origin of Heaven and Earth;

The Named is the mother of all things.

 Lao Tsu (c. 6th century

BC

)

N

AMES are used to refer to entities declared in a Java program. A declared

entity ( 6.1) is a package, class type, interface type, member (field or method) of a

reference type, parameter (to a method, constructor, or exception handler), or

local variable.

Names in Java programs are either simple, consisting of a single identifier, or

qualified, consisting of a sequence of identifiers separated by  

.

  tokens ( 6.2).

Every name introduced by a declaration has a

scope

 ( 6.3), which is the part

of the Java program text within which the declared entity can be referred to by a

simple name.

Packages and reference types (that is, class types, interface types, and array

types) have members ( 6.4). A member can be referred to using a qualified name

N.x

, where

N

 is a simple or qualified name and

x

 is an identifier. If

N

 names a

package, then

x

 is a member of that package, which is either a class or interface

type or a subpackage. If

N

 names a reference type or a variable of a reference type,

then

x

 names a member of that type, which is either a field or a method.

In determining the meaning of a name ( 6.5), Java uses the context of the

occurrence to disambiguate among packages, types, variables, and methods with

the same name.

Access control ( 6.6) can be specified in a class, interface, method, or field

declaration to control when

access

 to a member is allowed. Access is a different

concept from scope; access specifies the part of the Java program text within

which the declared entity can be referred to by a qualified name, a field access

expression ( 15.10), or a method invocation expression ( 15.11) in which the

method is not specified by a simple name. The default access is that a member can

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