How do I read from a json file in java and write a script?

I have a java program which transfers a file from a storage to an S3 storage. Right now we have hardcoded the values of the S3 bucket name and other config data for transfer of files. I have a json file which has the config data for multiple such files and I need to transfer them all. I need to write a script or a program which could trigger the necessary parts of the code, read data from my json file, change the hardcoded values and transfer the file. How should I do this?