A ForecastJobRequest object gets created with an existing non-null jobId. All other fields are optional for the request.

ForecastJobRequest forecastJobRequest = new ForecastJobRequest("forecasting-my-first-machine-learning-job"); 

The following arguments are optional.

forecastJobRequest.setExpiresIn(TimeValue.timeValueHours(48)); 
forecastJobRequest.setDuration(TimeValue.timeValueHours(24)); 

A ForecastJobResponse contains an acknowledgement and the forecast ID

boolean isAcknowledged = forecastJobResponse.isAcknowledged(); 
String forecastId = forecastJobResponse.getForecastId(); 

When executing a ForecastJobRequest in the following manner, the client waits for the ForecastJobResponse to be returned before continuing with code execution:

ForecastJobResponse forecastJobResponse = client.machineLearning().forecastJob(forecastJobRequest, RequestOptions.DEFAULT);

Executing a ForecastJobRequest can also be done in an asynchronous fashion so that the client can return directly. Users need to specify how the response or potential failures will be handled by passing the request and a listener to the asynchronous forecast-job method:

client.machineLearning().forecastJobAsync(forecastJobRequest, RequestOptions.DEFAULT, listener); 

The asynchronous method does not block and returns immediately. Once it is completed the ActionListener is called back using the onResponse method if the execution successfully completed or using the onFailure method if it failed.

A typical listener for forecast-job looks like:

ActionListener<ForecastJobResponse> listener = new ActionListener<ForecastJobResponse>() {
    @Override
    public void onResponse(ForecastJobResponse forecastJobResponse) {
        
    }

    @Override
    public void onFailure(Exception e) {
        
    }
};