Hi Jon,
I understand that service providers have a different set of rules (they
are usually not universally accessible classes) and therefore the
requirement for them to have public access modifier is merely a choice
JLS made to enforce a certain degree of strictness. Classes with default
(package-private) modifier could easily be allowed too, but I guess some
strictness is welcome. I just wanted to share what I observed: that the
javac error message is similar also when trying to access a public
nested class in a package-private enclosing class in an exported
package, from a different module, which has nothing to do with service
providers.
Regards, Peter
On 02/13/2017 08:10 PM, Jonathan Gibbons wrote:
Peter,
The circumstances of the analysis of service providers are very
different to the normal JLS rules regarding visibility and
accessibility of named items.
I know that we have some cleanup to do, for javac to "catch up" with
the latest updates to JLS, especially with regards to the difference
between "visibility" and "accessibility". Is that the issue you
concerned about, or is there something else about this message you
find confusing.
-- Jon
On 02/13/2017 09:08 AM, Peter Levart wrote:
Hi,
Just wanted to note that the confusing javac error message is not
specific to services and service providers.
Take the following example:
src/moda/module-info.java:
module moda {
exports pkga;
}
src/moda/pkga/Outer.java:
package pkga;
class Outer {
public static class Untouchable {
public static void touch() {
throw new AssertionError("Can't touch this!");
}
}
}
src/modb/module-info.java:
module modb {
requires moda;
}
src/modb/pkgb/Intruder.java:
package pkgb;
public class Intruder {
public static void main(String[] args) {
pkga.Outer.Untouchable.touch();
}
}
$ javac -d out --module-path out --module-source-path src `find src
-name '*.java'`
src/modb/pkgb/Intruder.java:6: error: package pkga is not visible
pkga.Outer.Untouchable.touch();
^
(package pkga is declared in module moda, which does not export it
to module modb)
1 error
Regards, Peter
On 02/09/2017 11:49 PM, Vicente Romero wrote:
Hi Alex,
Just to double check, the right javac behavior in this case should
be to issue similar errors in both cases like:
some position here: error: ServiceImpl is not public in
com.example.internal; cannot be accessed from outside package
some other position here: error: Outer.ServiceImpl is not public in
com.example.internal; cannot be accessed from outside package
without mentioning in any case anything about visibility right?
Thanks,
Vicente
On 02/07/2017 02:21 PM, Alex Buckley wrote:
On 2/7/2017 1:11 AM, Gunnar Morling wrote:
---
package com.example;
public interface SomeService {
public void foo();
}
---
package com.example.internal;
class Outer {
public static class ServiceImpl implements
com.example.SomeService {
public ServiceImpl() {}
public void foo() {}
}
}
---
package com.example.internal;
class ServiceImpl implements com.example.SomeService {
public ServiceImpl() {}
public void foo() {}
}
---
module com.example {
exports com.example;
provides com.example.SomeService with
com.example.internal.ServiceImpl;
provides com.example.SomeService with
com.example.internal.Outer.ServiceImpl;
}
---
Essentially, I'm wondering:
* Why Outer.ServiceImpl triggers the error about package visibility
while ServiceImpl doesn't (I had a look at the EDR JLS, but I
couldn't
find an explanation for that, happy about any specific pointers).
* Why Outer.ServiceImpl triggers "does not have a default
constructor"
(ServiceImpl does not). Maybe a hint would be nice that is caused by
Outer not having public access.
Thanks for showing the code. Since everything in the same module,
package visibility is not relevant and javac shouldn't mention it.
I suspect that javac is getting tripped up by the fact that
Outer.ServiceImpl is declared 'public' (as the JLS and
ServiceLoader both demand) but it isn't widely accessible, even
within the com.example module, due to Outer's default (package)
access. I believe the JLS and ServiceLoader rules are correct, so
it's a javac bug.
Alex
