Program: 32923
Project: 32923
Buggy source:
public static MultiLabelClfDataSet concatenateByColumn(MultiLabelClfDataSet dataSet1,MultiLabelClfDataSet dataSet2){
  int numDataPoints=dataSet1.getNumDataPoints();
  int numFeatures1=dataSet1.getNumFeatures();
  int numFeatures2=dataSet2.getNumFeatures();
  int numFeatures=numFeatures1 + numFeatures2;
  MultiLabelClfDataSet dataSet=MLClfDataSetBuilder.getBuilder().numDataPoints(numDataPoints).numFeatures(numFeatures).numClasses(dataSet1.getNumClasses()).dense(dataSet1.isDense()).missingValue(dataSet1.hasMissingValue()).build();
  int featureIndex=0;
  for (int j=0; j < numFeatures1; j++) {
    Vector vector=dataSet1.getColumn(j);
    for (    Vector.Element element : vector.nonZeroes()) {
      int i=element.index();
      double value=element.get();
      dataSet.setFeatureValue(i,featureIndex,value);
    }
    featureIndex+=1;
  }
  for (int j=0; j < numFeatures2; j++) {
    Vector vector=dataSet2.getColumn(j);
    for (    Vector.Element element : vector.nonZeroes()) {
      int i=element.index();
      double value=element.get();
      dataSet.setFeatureValue(i,featureIndex,value);
    }
    featureIndex+=1;
  }
  MultiLabel[] labels=dataSet1.getMultiLabels();
  for (int i=0; i < numDataPoints; i++) {
    dataSet.setLabels(i,labels[i]);
  }
  FeatureList featureList=new FeatureList();
  for (  Feature feature : dataSet1.getFeatureList().getAll()) {
    featureList.add(feature);
  }
  for (  Feature feature : dataSet2.getFeatureList().getAll()) {
    featureList.add(feature);
  }
  dataSet.setFeatureList(featureList);
  dataSet.setLabelTranslator(dataSet1.getLabelTranslator());
  dataSet.setIdTranslator(dataSet1.getIdTranslator());
  return dataSet;
}

Fixed version (ground truth):
public static MultiLabelClfDataSet concatenateByColumn(MultiLabelClfDataSet dataSet1,MultiLabelClfDataSet dataSet2){
  int numDataPoints=dataSet1.getNumDataPoints();
  int numFeatures1=dataSet1.getNumFeatures();
  int numFeatures2=dataSet2.getNumFeatures();
  int numFeatures=numFeatures1 + numFeatures2;
  MultiLabelClfDataSet dataSet=MLClfDataSetBuilder.getBuilder().numDataPoints(numDataPoints).numFeatures(numFeatures).numClasses(dataSet1.getNumClasses()).density(dataSet1.density()).missingValue(dataSet1.hasMissingValue()).build();
  int featureIndex=0;
  for (int j=0; j < numFeatures1; j++) {
    Vector vector=dataSet1.getColumn(j);
    for (    Vector.Element element : vector.nonZeroes()) {
      int i=element.index();
      double value=element.get();
      dataSet.setFeatureValue(i,featureIndex,value);
    }
    featureIndex+=1;
  }
  for (int j=0; j < numFeatures2; j++) {
    Vector vector=dataSet2.getColumn(j);
    for (    Vector.Element element : vector.nonZeroes()) {
      int i=element.index();
      double value=element.get();
      dataSet.setFeatureValue(i,featureIndex,value);
    }
    featureIndex+=1;
  }
  MultiLabel[] labels=dataSet1.getMultiLabels();
  for (int i=0; i < numDataPoints; i++) {
    dataSet.setLabels(i,labels[i]);
  }
  FeatureList featureList=new FeatureList();
  for (  Feature feature : dataSet1.getFeatureList().getAll()) {
    featureList.add(feature);
  }
  for (  Feature feature : dataSet2.getFeatureList().getAll()) {
    featureList.add(feature);
  }
  dataSet.setFeatureList(featureList);
  dataSet.setLabelTranslator(dataSet1.getLabelTranslator());
  dataSet.setIdTranslator(dataSet1.getIdTranslator());
  return dataSet;
}