NAMES

Scope of a Simple Name

6.3

6.3   Scope of a Simple Name

The

scope

 of a declaration is the region of the program within which the entity

declared by the declaration can be referred to using a simple name:

The scope of a package, as introduced by a

package

 declaration, is deter 

mined by the host system ( 7.4.3). All Java code is within the scope of the

standard package named

java

, so the package

java

 can always be referred to

by Java code.

The scope of a type imported by a single type import declaration ( 7.5.1) or

type import on demand declaration ( 7.5.2) is all the class and interface type

declarations ( 7.6) in the compilation unit in which the import declaration

appears.

The scope of a type introduced by a class type declaration ( 8.1.1) or interface

type declaration ( 9.1.1) is the declarations of all class and interface types in

all the compilation units ( 7.3) of the package in which it is declared.

The scope of a member declared in or inherited by a class type ( 8.2) or inter 

face type ( 9.2) is the entire declaration of the class or interface type. The

declaration of a member needs to appear before it is used only when the use is

in a field initialization expression ( 8.3.2,  12.4.2,  12.5). This means that a

compile time error results from the test program:

class Test {

int i = j;

//

compile time error: incorrect forward reference

int j = 1;

}

whereas the following example compiles without error:

class Test {

Test() { k = 2; }

int j = 1;

int i = j;

int k;

}

even though the constructor ( 8.6) for

Test

 refers to the field

k

 that is

declared three lines later.

The scope of a parameter of a method ( 8.4.1) is the entire body of the

method.

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