The issue is with the duplicate jar file. you can delete duplicat jar file.
Then clean your deployement directory.
https://forum.mendix.com/link/questions/117458
In our app IOUtils also existed in org.apache.commons.io-2.3.0.jar. Removing that jar solved this issue. It came with the UnitTesting App.-po
How to discover what jars contains the same class with the same package name?
Hope this answer helps for other cases with NoSuchMethodError or NoSuchMethodField
We are using Mendix 8.18.19 and had exactly the same error message with the import of an .xlsx file. First we noticed that we could import an .xls file but this is not what we wanted. The solution for us was to delete all the poi-jar files version 5.5.2 in the user lib and downgrade the Excel importer to 9.2.0, the latest available version just before Mendix upgraded the poi jar-files to 5.5.2. Now it worked fine. The userlib then looks like this (among other jar-files of course):
Import Excel Import Module and Excel Export Module(XLSImport) From Marketplace that have Apache poi library of version 4.xx
This will resolve your issue.
There are already a couple of forum posts about this one:
https://forum.mendix.com/link/questions/117458
https://forum.mendix.com/link/questions/117655
Double check the org.apache.poi ones. They all should have the same number (currently 5.2.2.) I had a org.apache.poi.poi-ooxml-schemas-4.1.2 file lingering that was causing this error in my case.
You could also try this tool: https://github.com/cinaq/mendix-userlib-cleaner
For safety first make a backup of your userlib directory before using this tool.
Regards,
Ronald
Make sure to clean the deployment directory of your project.
Project → Clean Deployment Directory.
I'm facing the exact same problem. I don't have any duplicate files in the userlib, and only the newest version. Also the Userlib Cleaner didn't solve the problem. Does anyone have another suggestion how to solve this problem?