SeekableByteChannel not seekable?

[Simone Bordet]

Hi,

seems that the SeekableByteChannel returned by Files.newByteChannel()
is not seekable if the path is from a zipfs, see exception below.

We do:

try (SeekableByteChannel channel = Files.newByteChannel(path,
StandardOpenOption.READ))
{
    channel.position(start); // BOOM
}

where path is a path from a ZipFileSystem.

Is that expected behavior? Seems strange that we get a
SeekableByteChannel that does not support seek - understandable given
the zipfs but still weird.

Maybe just needs explicit documentation?

I am an OpenJDK author and can file a bug if necessary.

Thanks!

2019-07-30 20:20:52.188:WARN:oejs.HttpChannel:qtp1717159510-47: /zipfs/large.dat
java.lang.UnsupportedOperationException
at com.sun.nio.zipfs.ZipFileSystem$3.position(ZipFileSystem.java:653)
at org.eclipse.jetty.util.resource.PathResource.writeTo(PathResource.java:591)
at org.eclipse.jetty.server.ResourceService.sendData(ResourceService.java:755)
at org.eclipse.jetty.server.ResourceService.doGet(ResourceService.java:294)
at org.eclipse.jetty.servlet.DefaultServlet.doGet(DefaultServlet.java:454)

-- 
Simone Bordet
---
Finally, no matter how good the architecture and design are,
to deliver bug-free software with optimal performance and reliability,
the implementation technique must be flawless.   Victoria Livschitz