How to get confidences of predictions in JAVA code

Greetings,
I made my RM plugin which works with predictions. I read predicted and true values as:

			ExampleSet exampleSet = getInput(ExampleSet.class);
			Iterator<Example> reader = exampleSet.iterator();
			while (reader.hasNext()) {
				Example example = reader.next();
				DataRow row = example.getDataRow();
				boolean trueGain = !(row
						.get(example.getAttributes().getLabel()) > 0.0);
				boolean predictedGain = !(row.get(example.getAttributes()
						.getPredictedLabel()) > 0.0);
				....
				double confidenceTrue = ????
				double confidenceFalse = ????
			}

How can I read confidences of predicted binominal values?

Thanks in advance.