code: public static int[] toClassificationVector(Iterable<MLClassificationRecord> data) {
          final List<Integer> responseVariables = new ArrayList<>();
          final List<Object> classifications = new ArrayList<>();
  
          for (MLClassificationRecord record : data) {
              final Object classification = record.getClassification();
              int classificationIndex = classifications.indexOf(classification);
              if (classificationIndex == -1) {
                  classifications.add(classification);
                  classificationIndex = classifications.size() - 1;
              }
              responseVariables.add(classificationIndex);
          }
  
          final int[] y = responseVariables.stream().mapToInt(i -> i).toArray();
          return y;
      }
docs: Generates a vector of classifications for each record.
  
  @param data
  @return