6.6.2

Details on

protected

 Access

NAMES

6.6.2   Details on

protected

 Access

A

protected

 member or constructor of an object may be accessed from outside

the package in which it is declared only by code that is responsible for the imple 

mentation of that object. Let

C

 be the class in which a

protected

 member or con 

structor is declared and let

S

 be the subclass of

C

 in whose declaration the use of

the

protected

 member or constructor occurs. Then:

If an access is of a

protected

 member (field or method), let

Id

 be its name.

Consider then the means of qualified access:

N

If the access is by a field access expression of the form

super.Id

, then the

access is permitted.

N

If the access is by a qualified name

Q.Id

, where

Q

 is a

TypeName

, then the

access is permitted if and only if

Q

 is

S

 or a subclass of

S

.

N

If the access is by a qualified name

Q.Id

, where

Q

 is an

ExpressionName

,

then the access is permitted if and only if the type of the expression

Q

 is

S

 or

a subclass of

S

.

N

If the access is by a field access expression

E.Id

, where

E

 is a

Primary

expression, or by a method invocation expression

E.Id(

. . .

)

, where

E

 is a

Primary

 expression, then the access is permitted if and only if the type of

E

is

S

 or a subclass of

S

.

Otherwise, if an access is of a

protected

 constructor:

N

If the access is by a superclass constructor invocation

super(

. . .

)

, then the

access is permitted.

N

If the access is by a class instance creation expression

new T(

. . .

)

, then the

access is not permitted. (A

protected

 constructor can be accessed by a

class instance creation expression only from within the package in which it

is defined.)

N

If the access is by an invocation of the method

newInstance

 of class

Class

( 20.3.6), then the access is not permitted.

6.6.3   An Example of Access Control

For examples of access control, consider the two compilation units:

package points;

class PointVec { Point[] vec; }

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