I tried that, you have input and output options in concourse but gradle doesn't have the build output folder path as option on the cli and you are not allowed to write into the input folder (the root folder path i.e. source)
I put the two tasks on the same job so I believe this will allow me to use the output *.jar from the first one into the next one (gradle -> docker).
The alternative is to upload the artifacts to S3 (or similar) but if I cannot access the artifacts from the first task I don't see how I can do this...
Thanks,
G.