I have close to no knowledge about java and could not have python-zxing working.

The README.md file states Initializing the barcode reader, you have to tell it where to find the ZXing core modules. It suggests /var/opt/zxing. However, there is no zxing directory in /var/opt after having followed the steps in Section "Usage".

After a few trials and error, I managed to run it by using the maven build directory:

zxing_scanner = zxing.BarCodeReader('/home/gael/04-build/zxing/zxing')
barcode = reader.decode('/tmp/image.jpg')

I wanted to install zxing globaly or as user but don't know how to do it. I noticed though that there is something related to zxing in ~/.m2/repository/com/google/zxing (there is ~/.m2/repository/com/google/zxing/core/3.2.1/core-3.2.1.jar but no core.jar) and wanted to use it. What I tried (I tried all commented lines with the same results):

# reader = zxing.BarCodeReader('/home/gael/.m2/repository/com/google/zxing/core/')
# reader = zxing.BarCodeReader('/home/gael/.m2/repository/com/google/zxing/core/3.2.1')
reader = zxing.BarCodeReader('/home/gael/.m2/repository')
barcode = reader.decode('/tmp/image.jpg')

I got:

Error: Could not find or load main class com.google.zxing.client.j2se.CommandLineRunner

I think it would be appropriate to give more details in the README.md file.