running oc command using fabric8 openshift client client

I am interacting with OpenShift platform in my project using fabric8 OpenShiftClient interface. I need to run the command oc exec {some pod name} -- df -h and get the result as a string in java. Can someone help me understand how can i do that?

I haven't found in the documentation of fabric8 any standard way to retrieve this information using the build in interface (for example, like getting the pods list which is very easy). So im guessing that i need to run this command in different way.