Where can I download the dependencies/jars needed for java mapping in SAP PI 7.5?
If you're on PI 7.5, than I think that you use NWDS for your java development.
The .jar files in question will actually exist in your PI system so one of your BASIS colleagues should be able to download them for you. I don't recall which ones you need exactly and where they reside in the file system but they will be there.
Check the below link and see if it helps,You can refer as per 7.3 version.