Warning: Cannot use jsr199 Javac from jrt-fs.jar"

[Jonathan Gibbons]

Keimpe,

While your use-case is about accessing alternate versions of javac, the 
underlying mechanism you are looking for is more general and not 
specific to javac.

The ability that you need, and which you're currently missing, is the 
ability to load code (modules) from an alternate JDK image.

If you could do that, you could load the module(s) you want into a new 
Layer, then from the Layer create a ServiceLoader, and from the 
ServiceLoader, iterate to find the desired impl of 
javax.tools.JavaCompiler, and thus avoid the need to use 
com.sun.tools.javac.api.JavacTool directly.

-- Jon


On 10/08/2015 09:47 AM, Keimpe Bronkhorst wrote:
> Jon,
>
> Users of JDeveloper want to be able to compile and run their code with
> any JDK on their filesystem, not just compile and run with the JDK
> JDeveloper is running on.
>
> The compile I could make work in JDK8 and before by getting a
> javax.tools.JavaCompiler from com.sun.tools.javac.api.JavacTool.create()
> all loaded through a classloader from tools.jar of the JDK the user
> wanted to use.
>
> I remember you previously mentioned you were considering a way to
> use JSR199 from any JDK other than the one of the current process.
>
> Keimpe Bronkhorst
> JDeveloper
>
>
> On 10/07/2015 06:01 PM, Keimpe Bronkhorst wrote:
>> /The underlying exception I get is: />/"Class 
>> oracle.jdevimpl.javacompiler.JDevJavaCompiler can not access a 
>> />/member of class com.sun.tools.javac.api.JavacTool (module 
>> />/jdk.compiler) with modifiers "public static", module jdk.compiler 
>> does />/not export com.sun.tools.javac.api to <unnamed module 
>> @1cfeea20>" />//>/Will there be a "public API" way to run JSR199 of 
>> any JDK9 installation? />//>/Keimpe Bronkhorst />/JDeveloper />//>/On 
>> 10/7/2015 6:54 PM, Keimpe Bronkhorst wrote: />>/It is possible in 
>> JDK8 and before to run JSR199 compilations using a />>/class loader 
>> that loads from tools.jar. I can't do something similar />>/in JDK9 
>> using a new jigsaw build, trying to load from jrt-fs.jar. I />>/get 
>> this: Warning: Cannot use jsr199 Javac from jrt-fs.jar". />>//>>/Does 
>> this mean you can only use the JSR199 as provided by 
>> />>/ToolProvider.getSystemJavaCompiler() of the current process in 
>> JDK9? />>//>>/Keimpe Bronkhorst />>/JDeveloper />//
> Keimpe,
>
> While we know that some "friends of javac" have been using its internal
> API, it would be good to know what specific internal features you have
> been using, so that we can see if there are alternatives on the public
> API, and maybe provide additional public API where appropriate.
>
> You can run tools like jdeps to find what dependencies you have on any
> internal API.
>
> -- Jon
>
>