[
https://issues.apache.org/jira/browse/PDFBOX-5758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17813894#comment-17813894
]
Axel Howind edited comment on PDFBOX-5758 at 2/3/24 10:47 AM:
--------------------------------------------------------------
-Sorry, this fixes only part of the problem. I will create an updated patch.-
I have to correct myself. Moving the LOG initialization to the beginning of the
class totally fixes this problem. So the patch is still valid.
was (Author: axh):
Sorry, this fixes only part of the problem. I will create an updated patch.
> ExceptionInInitializerError when unmapping is not supported
> -----------------------------------------------------------
>
> Key: PDFBOX-5758
> URL: https://issues.apache.org/jira/browse/PDFBOX-5758
> Project: PDFBox
> Issue Type: Bug
> Components: IO
> Reporter: Axel Howind
> Priority: Major
> Labels: patch
> Attachments:
> PDFBOX-5758__ExceptionInInitializerError_when_unmapping_is_not_supported.patch
>
>
> When unmapping is not supported, PdfBox throws an ExceptionInInitializerError
> that is not recoverable. The reason is that in IOUtils, the UNMAPPER static
> field is initialized before the Logger is created and when the unmapper can
> not be created, PdfBox tries to write an error message to the log:
>
> {code:java}
> public final class IOUtils
> {
> ...
> static
> {
> UNMAPPER = Optional.ofNullable(AccessController
> .doPrivileged((PrivilegedAction<Consumer<ByteBuffer>>)
> IOUtils::unmapper));
> }
> /**
> * Log instance.
> */
> private static final Logger LOG = LogManager.getLogger(IOUtils.class);
> ...
> private static Consumer<ByteBuffer> unmapper()
> {
> final Lookup lookup = lookup();
> try
> {
> ...
> }
> catch (SecurityException se)
> {
> LOG.error(
> "Unmapping is not supported because of missing permissions.
> Please grant at least the following permissions:
> RuntimePermission(\"accessClassInPackage.sun.misc\") "
> + " and ReflectPermission(\"suppressAccessChecks\")",
> se);
> }
> catch (ReflectiveOperationException | RuntimeException e)
> {
> LOG.error("Unmapping is not supported.", e);
> }
> return null;
> }{code}
>
> UPDATE:
> It is important to notice that this bug completely prevents loading of the
> IOUtils class (and in most cases crash the program), regardless of whether
> any functionality using mapping/unmapping is even used. So I think this
> should be considered a high priority bug.
> Excerpt of stacktrace:
> {noformat}
> Caused by: java.lang.ExceptionInInitializerError: Exception
> java.lang.NullPointerException [in thread "ForkJoinPool-1-worker-3"]
> at
> docdiff@1.6.0-SNAPSHOT/org.apache.pdfbox.io.IOUtils.unmapper(IOUtils.java:278)
> ~[docdiff:?]
> at
> java.base/java.security.AccessController.doPrivileged(AccessController.java:319)
> ~[?:?]
> at
> docdiff@1.6.0-SNAPSHOT/org.apache.pdfbox.io.IOUtils.<clinit>(IOUtils.java:64)
> ~[docdiff:?]
> at
> docdiff@1.6.0-SNAPSHOT/org.apache.pdfbox.Loader.loadPDF(Loader.java:196)
> ~[docdiff:?]
> at
> docdiff@1.6.0-SNAPSHOT/org.apache.pdfbox.Loader.loadPDF(Loader.java:176)
> ~[docdiff:?]
> at
> docdiff@1.6.0-SNAPSHOT/org.apache.pdfbox.Loader.loadPDF(Loader.java:159)
> ~[docdiff:?]{noformat}
> Line 278 is:
> {code:java}
> LOG.error("Unmapping is not supported.", e);{code}
> The reason is that LOG is initialized after UNMAPPER, but the initialisation
> of UNMAPPER accesses LOG in case of an error. That's due to this rule in the
> [JLS|[https://docs.oracle.com/javase/specs/jls/se11/html/jls-12.html#jls-12.4.2]]:
> {quote}Next, execute either the class variable initializers and static
> initializers of the class, or the field initializers of the interface, in
> textual order, as though they were a single block.
> {quote}
> By moving the LOG initialization to the beginning of the class, the UNMAPPER
> gets assigned to an empty Optional and no exception is thrown.
> I encountered this bug when jpackaging an application where obviously
> something in the generated application is missing that is needed for the
> unmapper to work. This was really a little bit hard to debug, because I
> logged all types of exceptions, but an Error is a Throwable that does not
> derive from Exception and usually just aborts the program and no log messages
> were generated. And the problem only happened when the program was not
> started with the debugger.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@pdfbox.apache.org
For additional commands, e-mail: dev-h...@pdfbox.apache.org
