javac --add-modules java.xml.bind for annotation processor?

[Jonathan Gibbons]

On 11/20/16 3:39 PM, Eirik Bjørsnøs wrote:
> Turns out that:
>
> a) Maven treats -J arguments in a special way which hides them from the
> debug log, but they're still passed on to javac
> b) Maven parses the javac output for error messages, but drops any output
> not following the javac output format.
>
> So using <arg>-J--add-modules=java.xml.bind</arg> does actually work!
>
> But my question remains:
>
> What's the difference between -J--add-modules and --add-modules  in javac?
>
> I guess --add-modules specifies modules that javac should allow compilation
> against, while -J--add-modules adds modules which should be visible to
> javac itself?
That's a pretty good analysis.   javac works with two environments: there's
the "compilation environment" which contains the elements being compiled,
and there's the "runtime environment" which contains the classes for javac
itself, and any annotation processors that are loaded and running.

>
> Eirik.
>
> On Sun, Nov 20, 2016 at 11:45 PM, Eirik Bjørsnøs <eirbjo at gmail.com> wrote:
>
>> Claes,
>>
>> Btw, the annotation processor has been _compiling_ fine all along.
>>
>> The problem happens when the example-module is compiled with the
>> annotation-processor on the javac -classpath
>>
>> Eirik.
>>
>> On Sun, Nov 20, 2016 at 11:23 PM, Claes Redestad <
>> claes.redestad at oracle.com> wrote:
>>
>>> Hi Eirik,
>>>
>>> compiling com.example.processor.ProcessorUsingJavaXmlBind standalone
>>> seems to work fine with --add-modules java.xml.bind - instead it
>>> appears as if maven-compiler-plugin doesn't preserve argument order, so
>>> you need to use the joined argument form in your pom.xml:
>>>
>>> <arg>--add-modules=java.xml.bind</arg>
>>>
>>> I tried this on your minified example, and seems to work. Thanks!
>>>
>>> /Claes
>>>
>>>
>>> On 2016-11-20 22:57, Eirik Bjørsnøs wrote:
>>>
>>>> Hi there!
>>>>
>>>> I'm giving Java 9 and Jigsaw a spin on a moderately complex project.
>>>> (Interestingly, the project is itself a module system, so we do stuff
>>>> like
>>>> annotation processing and dynamic reloading of class loader graphs and
>>>> services)
>>>>
>>>> I'm experienced enough with advanced Java to have shot myself in the foot
>>>> with a java.lang.ClassNotFoundException: java.lang.ClassNotFoundExcepti
>>>> on
>>>> :-) However, I've only recently been looking into Jigsaw in concrete
>>>> terms.
>>>> So please be kind when I expose my ignorance :-)
>>>>
>>>> Initially, I just want to see if I can get the project to compile on
>>>> Java 9.
>>>>
>>>> So I'm using --add-modules to javac here and there to add modules not
>>>> available to the unnamed module by default. (Not making any proper
>>>> modules
>>>> yet, that will be the next step).
>>>>
>>>> This seems to be working fine, except for one of our annotation
>>>> processors,
>>>> which happens to use JAXBContext from java.xml.bind.
>>>>
>>>> I added --add-modules to javac (via Maven configuration), but my
>>>> annotation
>>>> processor still can't load JAXBContext and fails with this message:
>>>>
>>>> $ java -version
>>>> java version "9-ea"
>>>> Java(TM) SE Runtime Environment (build 9-ea+144)
>>>> Java HotSpot(TM) 64-Bit Server VM (build 9-ea+144, mixed mode)
>>>>
>>>> $ mvn clean install -e
>>>>
>>>> This fails with:
>>>>
>>>> Caused by: java.lang.NoClassDefFoundError: javax/xml/bind/JAXBContext
>>>> at
>>>> com.example.processor.ProcessorUsingJavaXmlBind.process(Proc
>>>> essorUsingJavaXmlBind.java:24)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.processing.JavacProcessingE
>>>> nvironment.callProcessor(JavacProcessingEnvironment.java:959)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.processing.JavacProcessingE
>>>> nvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:875)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.processing.JavacProcessingE
>>>> nvironment.access$2100(JavacProcessingEnvironment.java:106)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.processing.JavacProcessingE
>>>> nvironment$Round.run(JavacProcessingEnvironment.java:1182)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.processing.JavacProcessingE
>>>> nvironment.doProcessing(JavacProcessingEnvironment.java:1290)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.main.JavaCompiler.processAn
>>>> notations(JavaCompiler.java:1260)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(J
>>>> avaCompiler.java:939)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl$1.call(Ja
>>>> vacTaskImpl.java:106)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl$1.call(Ja
>>>> vacTaskImpl.java:100)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.handleExc
>>>> eptions(JavacTaskImpl.java:137)
>>>> ... 28 more
>>>>
>>>> I've confirmed that this reproduces using only javac:
>>>>
>>>> $ cd example-module
>>>>
>>>> $ javac -d  target/classes -classpath
>>>> target/classes:$HOME/.m2/repository/com/example/annotation-p
>>>> rocessor/1.0-SNAPSHOT/annotation-processor-1.0-SNAPSHOT.jar:
>>>> -sourcepath src/main/java/ -target 1.9 -source 1.9 --add-modules
>>>> java.xml.bind src/main/java/com/example/module/SomeClass.java
>>>>
>>>> java.xml? true
>>>> java.xml.bind? false
>>>>
>>>>
>>>> An annotation processor threw an uncaught exception.
>>>> Consult the following stack trace for details.
>>>> java.lang.NoClassDefFoundError: javax/xml/bind/JAXBContext
>>>> at
>>>> com.example.processor.ProcessorUsingJavaXmlBind.process(Proc
>>>> essorUsingJavaXmlBind.java:24)
>>>> at
>>>> jdk.compiler/com.sun.tools.javac.processing.JavacProcessingE
>>>> nvironment.callProcessor(JavacProcessingEnvironment.java:959)
>>>>
>>>>
>>>> I've reduced this to a minimal-ish test case, available on Github:
>>>>
>>>> https://github.com/eirbjo/java-xml-bind-processor
>>>>
>>>> Here's the annotation processor:
>>>>
>>>> https://github.com/eirbjo/java-xml-bind-processor/blob/maste
>>>> r/annotation-processor/src/main/java/com/example/processor/
>>>> ProcessorUsingJavaXmlBind.java
>>>>
>>>> The class under compilation and the annotation:
>>>>
>>>> https://github.com/eirbjo/java-xml-bind-processor/blob/maste
>>>> r/example-module/src/main/java/com/example/module/SomeClass.java
>>>> https://github.com/eirbjo/java-xml-bind-processor/blob/maste
>>>> r/example-module/src/main/java/com/example/module/SomeAnnotation.java
>>>>
>>>>
>>>> Any clues?
>>>>
>>>> Cheers,
>>>> Eirik.
>>>>
>>>>