Apache FOP in a Java Applet - No ImagePreloader found for data

Question

I\'m looking at an issue in a mature commercial product.

In a nutshell, we are using part of the Apache POI library to read in a Word .DOC or .DOCX file, and convert

Answer 1

In case anyone else has something similar, this turned out to be caused by the way the project was being built in Maven.

Fop 1.0 and above use the xml-graphics-commons library to facilitate the image rendering. As mentioned in the question, this uses a plugin registry which is configured using the following files inside the JAR:

META-INF/services/org.apache.xmlgraphics.image.loader.spi.ImageConverter
META-INF/services/org.apache.xmlgraphics.image.loader.spi.ImageLoaderFactory
META-INF/services/org.apache.xmlgraphics.image.loader.spi.ImagePreloader

...each of these contains a list of the image decoders which will be supported.

The problem is that xml-graphics-common ships these files with a sensible list of defaults, while FOP also has a conflicting set of defaults, which for some weird reason disable all of the image decoders, and that one was taking priority.

To solve the problem, I made sure that my maven pom.xml file imported xml-graphics-common before FOP, so that its defaults took precedence, and at that point everything sprang to life.

I am still not sure why the code was working correctly as a standalone test program, but I suspect it was the way the classpath was being handled being different to it running in plugin mode.