Thad,
A quick read of https://github.com/jai-imageio/jai-imageio-core suggests
a possible cause.
The library is using the SPI plugin mechanism of ImageIO.
I haven't confirmed this with a code inspection but what I assume is
happening is that the web application is registering an extension at the
JRE level with ImageIO but with the implementation only visible to the
web application. With multiple web applications you are ending up with a
single registration (not sure if it is the first or the last web
application that tries to register it) and all web applications try and
use the same one.
I'm surprised you didn't have CNFE even when using the same version in
multiple web applications.
The fix is to move the library JARs out of the web application and into
$CATALINA_BASE/lib. That way you will have a single registration that is
visible to all web applications. That assumes there is a version that
will work for all the web applications. If the web applications need
different versions you will likely need a Tomcat instance for each version.
HTH,
Mark
On 12/04/2025 21:22, Thad Humphries wrote:
I have a problem that appears to be one webapp in Tomcat 9 having a portion
of its classpath masked by another webapp. I am running Tomcat 9 (versions
see below) on macOS 15.4 with Amazon's OpenJDK 11.0.22+7-LTS.
I have 3 webapps all of which use PDFBox 2 and jai-imageio-core
(standalone) v1.4.0, largely for converting pages of a PDF to a Java
BufferedImage and then to PNG for display in a browser. None of these
webapps use com.twelvemonkeys.imageio.
Last week I was presented with a PDF with JPEG2000 images on some pages.
Having no luck on a command line with PDFBox 2 and jai-imageio-jpeg2000, I
tried PDFBox 3. That worked so I updated my most recent app to PDFBox 3 and
added jai-imageio-jpeg2000. That worked fine from NetBeans and the Tomcat
9.0.67 dev server. However when I deployed my app to Tomcat 9.0.80 with the
other two apps, the JPEG2000 images failed, producing this in my app's log:
ERROR PDFStreamEngine.operatorException() - Cannot read JPEG2000 image:
Java Advanced Imaging (JAI) Image I/O Tools are not installed
org.apache.pdfbox.filter.MissingImageReaderException: Cannot read JPEG2000
image: Java Advanced Imaging (JAI) Image I/O Tools are not installed
at org.apache.pdfbox.filter.Filter.findImageReader(Filter.java:171)
~[pdfbox-3.0.4.jar:3.0.4]
...
Both jai-imageio-core and jai-imageio-jpeg2000 are in WEB-INF/lib so why
wasn't JPEG2000 found?
I downloaded Tomcat 9.0.104 and deployed my new app. The JPEG2000 images
were fine. I installed one of the older apps via manager, and my new app
still worked. I restarted Tomcat and the images failed. Then I copied
jai-imageio-jpeg2000 to the old app's WEB-INF/lib, restarted Tomcat, and
the JPEG2000 images were again fine.
I've since tried this test with both 9.0.80 and 9.0.104 and see the same
results. Interestingly, on startup I see the older app's deployment
descriptor loads first in catalina.out. I understand the order is
non-deterministic, but it appears that if the first webapp with
jai-imageio-core does not jai-imageio-jpeg2000 with it, the second app
can't find jai-imageio-jpeg2000 in its WEB-INF/lib.
I know jai-imageio in webapps is a strange beast, going back to the
original Sun versions and Tomcat 4 and 5. When I was running TwelveMonkeys
I had a special context listener for that library, but I dropped that
library years ago because jai-imageio-core standalone was all I needed.
Any thoughts, ideas, or known problems with the combinations I've described
above? Any solutions other than copying jai-imageio-jpeg2000 to the other
apps' WEB-INF/lib?
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