(update) Use "default" keyword for default visibility

[Adrian Kuhn]

On Mar 5, 2009, at 00:28 , Joseph D. Darcy wrote:

> Not all modifiers are applicable in all places.  For example,  
> "private" cannot appear on the methods of an interface.   A more  
> convincing specification would list explicitly the grammar changes  
> and updated JLS sections.

That's feels like writing up house rules for D&D :)

Changes to http://java.sun.com/docs/books/jls/download/langspec-3.0.pdf

6

[..] The default access is that a member can be accessed anywhere  
within the package that contains its declaration; other possibilities  
are public, protected, and private.

[* Actually, this is not true for interface members and enum  
constructors! The introduction of the chapters seems to be prose  
anyway, so I dont fix that for now. ]

6.6.1 second item

- [...] If a top level class or interface type is declared "package"  
or has no access modifier, then it may be accessed only from within  
the package in which it is declared.

6.6.1 last item

- Otherwise, if the member or constructor is declared "package" or has  
no access modifier, then access is permitted only when it occurs from  
within the package in which the type is declared.

6.6.4

If a class lacks the public modifier or is declared "package", access  
to the class declaration is limited to the package in which it is  
declared (§6.6).

[* Example may need to be updated.]

6.6.5

If the "package" modifier is specified or none of the access modifiers  
are specified, [..]

If a public class has a method or constructor with default access or  
"package" modifier, then this method or constructor is not accessible  
to or inherited by a subclass declared outside this package.

[* Example may need to be updated.]

8

Field, method, member class, member interface, and constructor  
declarations may include the access modifiers (§6.6) package, public,  
protected, or private.

8.1.1

/ClassModifier: one of/
	/Annotation/ package public protected private
	abstract static final strictfp
	
[* I could not find a sentence that declares multiple access modifiers  
to be a compile-time error. Where is this stated for classes if not  
here?]
	
8.2.1.1

[* Example may need to be updated.]
	
8.3.1

/FieldModifier: one of/
	/Annotation/ package public protected private
	static final transient volatile
	
A compile-time error occurs [..] if a field declaration has more than  
one of the access modifiers package, public, protected, and private.

8.4.3

/MethodModifier: one of/
	/Annotation/ package public protected private abstract
	static final synchronized native strictfp
	
A compile-time error occurs [..] if a method declaration has more than  
one of the access modifiers package, public, protected, and private.

8.4.8

[..] of the superclass and superinterfaces that are public, protected,  
"package" or declared with default access in the same package as C and  
[..]

[...]

- /m2/ is public, protected, package or declared with default access  
in the same package
as C, or

[...]

8.4.8.4

If the overridden or hidden method is "package" or has default access,  
then the overriding or hiding method must not be private; otherwise, a  
compile-time error occurs.

8.5.1

The access modifiers package, public, protected, and private are  
discussed in §6.6. A compile-time error occurs if a member type  
declaration has more than one of the access modifiers package, public,  
protected, and private.

8.8.3

/ConstructorModifier: one of/
	/Annotation/ package public protected private
	
The access modifiers package, public, protected, and private are  
discussed in §6.6. A compile-time error occurs [..] if a constructor  
declaration has more than one of the access modifiers package, public,  
protected, and private.

It is a compile-time error if the constructor of an enum type (§8.9)  
is declared
package, public or protected.

[* BTW, another irregularity here: for enum constructors, no access  
modifier means private not default access. This may violate the  
principle of least surprise. ]

8.8.9 5th paragraph

[..] otherwise, if the class is declared "package" or has no access  
modifier, the default constructor is implicitly given the access  
modifier "package".

9.1.1

/InterfaceModifier: one of/
	/Annotation/ package public protected private
	abstract static strictfp
	
[* Again, I could not find a sentence that declares multiple access  
modifiers to be a compile-time error. Where is this stated for  
interfaces if not here?]

9.3

[* Would need a change if we want to allow interfaces members to be  
package visible. See Alex Buckley's blog posts. Currently, if  
interface members do have no access modifiers, they are assumed to be  
public. ]

9.4

[* Same as above.]

12.3.3 first item

[..] because the field or method was declared private, protected,  
"package", or default access (not public), or because the class was  
not declared public.

13.4.7

[..] Less access is permitted if the access modifier is changed from  
"package" access to
private access; from protected access to "package" or privat access;  
or from public access to protected, "package", or private access. [..]

14.3

It is a compile-time error if a local class declaration contains any  
one of the following access modifiers: package, public, protected,  
private, or static.

[* Is this correct? I guess, since no access modifier on local class  
means local visibility not default visibility. ]

18.1

/Modifier:/
	/Annotation/
	package
	public
	protected
	...


>> COMPATIBILITY:
>> A compiler switch is offered to set either strict or compatibility   
>> mode. In strict mode, an error is issued if a member has not   
>> visibility modifier.
>
> That would be a non-starter if mandatory; it would mean gratuitous  
> source incompatibilities between JDK 7 and earlier source levels.   
> An annotation processor can be written to do this to enforce local  
> coding conventions.

Okay, dropped.

cheers,
AA