modulepath and classpath mixture

[Robert Scholte]

Hi,

it seems that simply adding -addmods ALL-MODULE-PATH isn't enough to  
compile the test-sources, and some already referred to it.

Here's the compiler error:
maven-builder-support/src/test/java/org/apache/maven/building/DefaultProblemTest.java:[1,1]  
package exists in another module: maven.builder.support

Let me quote Alan from one of the first responses on this thread:
"For the tests then I assume they are in the same packages as the sources  
under src/main/java, is that right?

In that case I think you will want to compile the tests as if they are  
part of the module:

   javac  -Xmodule:m  -d testclasses/m  -mp m.jar  test/java/...

where m is the module name and the module (with sources in src/main/java)  
has already been compiled and then packaged as m.jar. The  
-Xmodule:<module> option tells the compiler that you compiling the test  
classes as if they are part of module m. There is no module-info.java in  
the test tree."

To me it seems like the need for knowing the module name keeps returning.
This increases the need for a proper implementation of the  
maven-compiler-plugin as a multirelease JAR.
The pattern as shown during FOSDEM showed that the idea works, but it is  
not solid enough.
And the next question would be: can Maven (or actually Plexus ClassWorld)  
handle this?

I'll need to work out the things to be done and try to get more Maven  
developers involved.

thanks,
Robert

On Wed, 16 Mar 2016 21:55:01 +0100, <mark.reinhold at oracle.com> wrote:

> 2016/2/27 3:25 -0800, rfscholte at apache.org:
>> I noticed[1] that -addmods already has a special option: ALL-SYSTEM
>> What I'm looking for is something like ALL-MP or ALL-MODULEPATH, which
>> simply exposes all modules on the modulepath to the classpath. The set  
>> of
>> moduleEntries on the modulePath are already chosen with care and are in
>> the end all required to be able to compile the test-classes without the
>> need of knowing the name of the module being used to compile with.
>
> We added a special ALL-MODULE-PATH token to the -addmods option, with
> this description now in JEP 261 (http://openjdk.java.net/jeps/261):
>
>   As a further special case, if `<module>` is `ALL-MODULE-PATH` then all
>   observable modules found on module paths are added to the root set.
>   `ALL-MODULE-PATH` is valid at compile time when compiling classes in  
> the
>   unnamed module, and at run time when the main class of the application  
> is
>   loaded from the class path into the unnamed module.
>
> This change is in Jigsaw EA build #4647 (https://jdk9.java.net/jigsaw/).
> Please try it out and let us know what you think.
>
> - Mark