[
https://issues.apache.org/jira/browse/VFS-683?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16694097#comment-16694097
]
Daryl Odnert commented on VFS-683:
----------------------------------
[~ottobackwards] - In general, are {{FileObject}} instances supposed to be
thread-safe? The documentation is unclear about this.
My colleague and I are suspicious of the caching that's happening in
{{org.apache.commons.vfs2.provider.AbstractFileSystem.resolveFile}}. [Source
code is
here|https://svn.apache.org/viewvc/commons/proper/vfs/tags/commons-vfs2-project-2.2/commons-vfs2/src/main/java/org/apache/commons/vfs2/provider/AbstractFileSystem.java?revision=1811361&view=markup#l303].
With caching happening here, the same {{FileObject}} instance could be
returned to multiple threads, which would lead to a problem if more than one of
those threads try to read the contents simultaneously.
> Thread safety issue in VFSClassLoader - NullPointerException thrown
> -------------------------------------------------------------------
>
> Key: VFS-683
> URL: https://issues.apache.org/jira/browse/VFS-683
> Project: Commons VFS
> Issue Type: Bug
> Affects Versions: 2.2
> Reporter: Daryl Odnert
> Priority: Major
>
> In my application, I have two instances of the {{VFSClassLoader}}, each of
> which is being used in a distinct thread. Both {{VFSClassLoader}} instances
> refer to the same compressed file resource described by a {{FileObject}} that
> is passed to the class loader's constructor. Intermittently, the application
> throws an exception with the stack trace shown below. So, there seems to be
> either a race condition in the code or an undocumented assumption here. If it
> is unsupported for two {{VFSClassLoader}} instances to refer to the same
> resource (file), then that assumption should be documented. But if that is
> not the case, then there is a race condition bug in the implementation.
> {noformat}
> 43789 WARN {} c.a.e.u.PreferredPathClassLoader - While loading class
> org.apache.hive.jdbc.HiveDatabaseMetaData, rethrowing unexpected
> java.lang.NullPointerException: Inflater has been closed
> java.lang.NullPointerException: Inflater has been closed
> at java.util.zip.Inflater.ensureOpen(Inflater.java:389)
> at java.util.zip.Inflater.inflate(Inflater.java:257)
> at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:152)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:284)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
> at
> org.apache.commons.vfs2.util.MonitorInputStream.read(MonitorInputStream.java:91)
> at org.apache.commons.vfs2.FileUtil.getContent(FileUtil.java:47)
> at org.apache.commons.vfs2.impl.Resource.getBytes(Resource.java:102)
> at
> org.apache.commons.vfs2.impl.VFSClassLoader.defineClass(VFSClassLoader.java:179)
> at
> org.apache.commons.vfs2.impl.VFSClassLoader.findClass(VFSClassLoader.java:150)
> at
> com.atscale.engine.utils.PreferredPathClassLoader.findClass(PreferredPathClassLoader.scala:54)
> {noformat}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
