Replacing default FileSystemProvider

[Alan Bateman]

On 21/03/2021 08:35, Michael Hall wrote:
> :
>
> So far I haven’t been able to duplicate the error with the simple test 
> case. The error does appear to begin right after 1.8 at java 9.
>
> It seems similar to these issues…
> https://bugs.openjdk.java.net/browse/JDK-8058876 
> <https://bugs.openjdk.java.net/browse/JDK-8058876>. Overriding the 
> default file system provider fails with a modular image
> https://bugs.openjdk.java.net/browse/JDK-8059939 
> <https://bugs.openjdk.java.net/browse/JDK-8059939>. java/nio/file/spi/SetDefaultProvider.java 
> fails with modular image
>
Those issues were in the jigsaw repo so didn't impact any GA release.

That said, there has been refactoring in this area since JDK 8 in order 
to allow access to the file system during VM initialization. This all 
happens before a custom file system provider is located and set. So are 
you saying that the NPE started with JDK 9 or a more recent release? We 
have tests that exercise this mechanism so I would be surprised if there 
is something fundamentally broken. The only other thing that comes to 
mind is the zip/JAR code which has changed significantly in recent 
releases (the zip/JAR code needs to use the builtin file system provider 
when accessing the file system to load the custom file system provider). 
Finally, just to rule this out, your provider isn't making direct use of 
the sun.nio.* classes, right?

-Alan