code: public Observable<JobTargetGroupInner> getAsync(String resourceGroupName, String serverName, String jobAgentName, String targetGroupName) {
          return getWithServiceResponseAsync(resourceGroupName, serverName, jobAgentName, targetGroupName).map(new Func1<ServiceResponse<JobTargetGroupInner>, JobTargetGroupInner>() {
              @Override
              public JobTargetGroupInner call(ServiceResponse<JobTargetGroupInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets a target group.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param serverName The name of the server.
  @param jobAgentName The name of the job agent.
  @param targetGroupName The name of the target group.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the JobTargetGroupInner object