REST api to Execute Import Action Error

I have a java application where I'm trying to execute an import action using the REST API and am getting the returned status of 415 (unsupported media type) from the post.  I'm following the syntax defined in the online help: : Client client = ClientBuilder.newClient(); Entity payload = Entity.text(""); Response response ="{workspaceID}/models/{modelID}/imports/{importId}/tasks/")   .request(MediaType.TEXT_PLAIN_TYPE)   .header("Authorization", "Basic encoded_username:password")   .header("Accept", "application/json")   .post(payload); and replacing {workspaceID}, {modelID}, and {importId} with the values from the GET API calls.  Tried other media types but still getting the same error.  Any help is appreciated.