code: @Override
      public int predict(double[] x, double[] posteriori) {
          Arrays.fill(posteriori, 0.0);
  
          for (int i = 0; i < trees.length; i++) {
              posteriori[trees[i].predict(x)] += alpha[i];
          }
  
          double sum = Math.sum(posteriori);
          for (int i = 0; i < k; i++) {
              posteriori[i] /= sum;
          }
  
          return Math.whichMax(posteriori);
      }
docs: Predicts the class label of an instance and also calculate a posteriori
  probabilities. Not supported.