We are processing a Word template that was created with Word 365 (Version 2202 Build 16.0.14931.20648) in Docx4J. Once the file was modified by our Java application, Word will show an error message when we open the document. The message will state that the file contains unreadable content and that Word needs to repair it. This works fine and the document will eventually open, however, the message is annoying.
I assume that the error message is related to a namespace issue (see this question). That issue was resolved with docx4j v. 8.2.9, which defines the missing namespaces properly.
However, I'm stuck with docx4j 3.3.3 and cannot update. The fix seems rather simple in the GitHub commit, so I wonder, if there is any way to resolve the issue myself. All I have in my code, is a WordprocessingMLPackage object. Can I add or append namespace definitions to that object or it's sub-properties somehow?
You can't add the namespace definitions to the WordprocessingMLPackage object.
You'll need to get the source code for 3.3.3 from https://github.com/plutext/docx4j/tree/docx4j-3.3.3 then copy the new NamespacePrefixMappings content into it, then build it. You can then deploy this new jar file.
If you wanted to try to avoid compiling the source code, you'd have 2 alternatives to try (since docx4j doesn't implement the stategy pattern there). I don't expect these to work!
One is to replace the relevant classes at runtime. For this, see How to replace classes in a running application in java ?
The other is to replace the relevant classes in your jar file, which is just a zip file.
You'd need to get the new class from docx4j 8.2.9.
Please note that sometimes, there are also changes to ContentTypeManager and ContentTypes; see for example https://github.com/plutext/docx4j/commit/d4d02d3fa6e7bf98f35d1f0520e62eb8aef06cba
That commit introduces new parts, and you'll run into problems if you update ContentTypeManager without those.
So you might be tempted to try to replace NamespacePrefixMappings in your existing jar.
But the interfaces it implements changed at https://github.com/plutext/docx4j/commit/65fb843a26b5893200a1824c04c826db2db7940c#diff-70242e2f5ec56be77fe15322526f4530b02e8eafdcb9ae16b60b2220f62e0632
See further https://github.com/plutext/docx4j/commits/VERSION_8_3_8/docx4j-core/src/main/java/org/docx4j/jaxb/NamespacePrefixMappings.java so that is going to cause you problems.
The upshot is you'll need to get the source code for 3.3.3 from https://github.com/plutext/docx4j/tree/docx4j-3.3.3 then copy the new NamespacePrefixMappings content into it (ie except the interface changes), then build it. If you do this, you may as well just deploy your new jar file.