[External] : Re: JEP 476: Clarification on Package Export Behavior in Java Modules

[Thiago Henrique Hupner]

Source structure:

src
    |   module-info.java
    \---my
        \---nice
            \---project
                |   Main.java
                \---pkg
                    +---a
                    |       SomeInterface.java
                    \---b
                            SomeRecord.java

I've tried both commands with and without the module import and they both
fail:

java --enable-preview src/my/nice/project/Main.java


javac --release 23 --enable-preview -d ./mod ./src/module-info.java
./src/my/nice/project/Main.java
./src/my/nice/project/pkg/a/SomeInterface.java
./src/my/nice/project/pkg/b/SomeRecord.java

However, exporting a package to the my.nice.project module and including
the module import both commands work.


.\src\my\nice\project\pkg\a\SomeInterface.java:7: error: cannot find symbol
    public SomeRecord someMethod();
           ^
  symbol:   class SomeRecord
  location: interface SomeInterface
.\src\my\nice\project\Main.java:7: error: cannot find symbol
        SomeInterface someInterface = new SomeInterface() {
        ^
  symbol:   class SomeInterface
  location: class Main
.\src\my\nice\project\Main.java:7: error: cannot find symbol
        SomeInterface someInterface = new SomeInterface() {
                                          ^
  symbol:   class SomeInterface
  location: class Main
.\src\my\nice\project\Main.java:9: error: cannot find symbol
            public SomeRecord someMethod() {
                   ^
  symbol: class SomeRecord
.\src\my\nice\project\Main.java:8: error: method does not override or
implement a method from a supertype
            @Override
            ^
.\src\my\nice\project\Main.java:10: error: cannot find symbol
                return new SomeRecord();
                           ^
  symbol: class SomeRecord
6 errors


Best regards,

Thiago

Em sex., 13 de set. de 2024 às 15:53, Alex Buckley <alex.buckley at oracle.com>
escreveu:

> If removing the imports doesn't fix the errors, then I'm suspicious of
> your compiler setup.
>
> Please describe on this mailing list the commands you're using and the
> actual javac errors that you see.
>
> Alex
>
> On 9/13/2024 9:41 AM, Thiago Henrique Hupner wrote:
> > Removing the imports still doesn't fix the errors.
> >
> > I've create a Github repo with the reproducer: https://github.com/
> > Thihup/module-import-bug
> >
> > Best regards,
> >
> > Thiago
> >
> >
> > Em sex., 13 de set. de 2024 às 12:41, Alex Buckley
> > <alex.buckley at oracle.com <mailto:alex.buckley at oracle.com>> escreveu:
> >
> >     I assume that the package my.nice.project is colocated with the other
> >     two packages -- my.nice.project.pkg.{a,b} -- in the module
> >     my.nice.project.
> >
> >     If so, then all three packages should be able to access each others'
> >     public types (SomeInterface, SomeRecord) without error.
> >
> >     The fact that you're getting an error looks like a javac bug.
> >
> >     You don't need to `import module my.nice.project` in the source
> >     files of
> >     that module. Try removing those imports and see if
> my.nice.project.Main
> >     compiles (it should).
> >
> >     Alex
> >
> >     On 9/13/2024 5:00 AM, Thiago Henrique Hupner wrote:
> >      > Dear Amber Team,
> >      >
> >      > I hope you're doing well. I’ve encountered a behavior related to
> JEP
> >      > 476: Module Import Declarations and wanted to ask for
> clarification.
> >      >
> >      > I’m working with a module setup where two packages are defined
> >     but not
> >      > initially exported:
> >      >
> >      > |module my.nice.project { //exports my.nice.project.pkg.a to
> >      > my.nice.project; //exports my.nice.project.pkg.b to
> >     my.nice.project; } |
> >      >
> >      > Here’s a simplified version of the code structure:
> >      >
> >      >
> >      > |package my.nice.project;
> >      > |
> >      > |
> >      > |import module my.nice.project;|
> >      >
> >      > |
> >      > |public class Main { public static void main(String[] args)
> >      > { SomeInterface someInterface = new SomeInterface() { @Override
> >     public
> >      > SomeRecord someMethod() { return new SomeRecord(); } }; } }|
> >      >
> >      > |
> >      > |
> >      > |package my.nice.project.pkg.a; import module my.nice.project;|
> >      > |
> >      > |
> >      > |public interface SomeInterface { public SomeRecord someMethod();
> }|
> >      >
> >      > |package my.nice.project.pkg.b; public record SomeRecord() {} |
> >      >
> >      > When attempting to compile this code with the exports commented
> >     out, I
> >      > received several "cannot find symbol" errors. However, after
> >      > uncommenting the exports:
> >      >
> >      >
> >      > |exports my.nice.project.pkg.a to my.nice.project; exports
> >      > my.nice.project.pkg.b to my.nice.project; |
> >      >
> >      > The code compiled and ran as expected.
> >      >
> >      > Given this behavior, I wanted to confirm if this restriction on
> >     package
> >      > visibility within a module is the intended design under the Amber
> >      > project and the module system, or if there’s another approach or
> >     best
> >      > practice I might be overlooking in terms of package exports.
> >      >
> >      > Thank you for your time and insight.
> >      >
> >      > Best regards,
> >      >
> >      > Thiago
> >      >
> >
>
>
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