Where can I download rest-data-service jar file referenced in Chapter 4 lab?

Thank you for answering my query.

When I execute - 

C:\Users\dgopal\Desktop\Cloud Foundry\class-artifacts>cf push roster1 -b "https://github.com/cloudfoundry/java-buildpack" -m 512M --random-route

I get the below error

   -----> Java Buildpack 553f2c6 | https://github.com/cloudfoundry/java-buildpack#553f2c6

   [Buildpack]                      ERROR Finalize failed with exception #<RuntimeError: No container can run this application. Please ensure that you've pushed a valid JVM artifact or artifacts using the -p command line argument or path manifest entry. Information about valid JVM artifacts can be found at https://github.com/cloudfoundry/java-buildpack#additional-documentation. >

   No container can run this application. Please ensure that you've pushed a valid JVM artifact or artifacts using the -p command line argument or path manifest entry. Information about valid JVM artifacts can be found at https://github.com/cloudfoundry/java-buildpack#additional-documentation.

   Failed to compile droplet: Failed to run finalize script: exit status 1

If I specify just java-buildpack, it gives me an error saying invalid buildpack.

What am I doing wrong?