Convert .js to .java files or fork from exsisting java codes and modify the data structure.

create the chaincode in java with given data structure fields for api calls. and build with gradle.

https://github.com/hyperledger/fabric-sdk-java
Or fabric sample chaincodes like fabcar, marbles for ref.

For experienced java code it takes a couple of hours to do.
People understands Java/Javascript/Hyperleder chaincode, Go through the repos, and ping me if you can deliver it.