Program: 56522
Project: 56522
Buggy source:
/** 
 * not setXAxisTitle() because   {@link XSSFCategoryAxis} doesn't have API to get title. 
 */
@Override protected void importChart(Sheet poiSheet,NSheet sheet){
  List<ZssChartX> charts=importXSSFDrawings((XSSFSheet)poiSheet);
  for (  ZssChartX zssChart : charts) {
    XSSFChart xssfChart=(XSSFChart)zssChart.getChart();
    ClientAnchor clientAnchor=xssfChart.getPreferredSize();
    int width=getXSSFWidthInPx(poiSheet,clientAnchor);
    int height=getXSSFHeightInPx(poiSheet,clientAnchor);
    NViewAnchor viewAnchor=new NViewAnchor(clientAnchor.getRow1(),clientAnchor.getCol1(),width,height);
    NChart chart=null;
    CategoryData categoryData=null;
switch (xssfChart.getChartType()) {
case Area:
      chart=sheet.addChart(NChartType.AREA,viewAnchor);
    categoryData=new XSSFAreaChartData(xssfChart);
  chart.setGrouping(convertGrouping(((XSSFAreaChartData)categoryData).getGrouping()));
break;
case Area3D:
chart=sheet.addChart(NChartType.AREA,viewAnchor);
categoryData=new XSSFArea3DChartData(xssfChart);
chart.setGrouping(convertGrouping(((XSSFArea3DChartData)categoryData).getGrouping()));
break;
case Bar:
chart=sheet.addChart(NChartType.BAR,viewAnchor);
categoryData=new XSSFBarChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFBarChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFBarChartData)categoryData).getGrouping()));
break;
case Bar3D:
chart=sheet.addChart(NChartType.BAR,viewAnchor);
categoryData=new XSSFBar3DChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFBar3DChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFBar3DChartData)categoryData).getGrouping()));
break;
case Bubble:
chart=sheet.addChart(NChartType.BUBBLE,viewAnchor);
XYZData xyzData=new XSSFBubbleChartData(xssfChart);
importXyzSeries(xyzData.getSeries(),chart);
break;
case Column:
chart=sheet.addChart(NChartType.COLUMN,viewAnchor);
categoryData=new XSSFColumnChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFColumnChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFColumnChartData)categoryData).getGrouping()));
break;
case Column3D:
chart=sheet.addChart(NChartType.COLUMN,viewAnchor);
categoryData=new XSSFColumn3DChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFColumn3DChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFColumn3DChartData)categoryData).getGrouping()));
break;
case Doughnut:
chart=sheet.addChart(NChartType.DOUGHNUT,viewAnchor);
categoryData=new XSSFDoughnutChartData(xssfChart);
break;
case Line:
chart=sheet.addChart(NChartType.LINE,viewAnchor);
categoryData=new XSSFLineChartData(xssfChart);
break;
case Line3D:
chart=sheet.addChart(NChartType.LINE,viewAnchor);
categoryData=new XSSFLine3DChartData(xssfChart);
break;
case Pie:
chart=sheet.addChart(NChartType.PIE,viewAnchor);
categoryData=new XSSFPieChartData(xssfChart);
break;
case Pie3D:
chart=sheet.addChart(NChartType.PIE,viewAnchor);
categoryData=new XSSFPie3DChartData(xssfChart);
break;
case Scatter:
chart=sheet.addChart(NChartType.SCATTER,viewAnchor);
XYData xyData=new XSSFScatChartData(xssfChart);
importXySeries(xyData.getSeries(),chart);
break;
case Stock:
chart=sheet.addChart(NChartType.STOCK,viewAnchor);
categoryData=new XSSFStockChartData(xssfChart);
break;
default :
continue;
}
if (xssfChart.getTitle() != null) {
chart.setTitle(xssfChart.getTitle().getString());
}
chart.setThreeD(xssfChart.isSetView3D());
chart.setLegendPosition(convertLengendPosition(xssfChart.getOrCreateLegend().getPosition()));
if (categoryData != null) {
importSeries(categoryData.getSeries(),chart);
}
}
}

Fixed version (ground truth):
/** 
 * Not import X & Y axis title because   {@link XSSFCategoryAxis} doesn't provide API to get title. 
 */
@Override protected void importChart(Sheet poiSheet,NSheet sheet){
  List<ZssChartX> charts=importXSSFDrawings((XSSFSheet)poiSheet);
  for (  ZssChartX zssChart : charts) {
    XSSFChart xssfChart=(XSSFChart)zssChart.getChart();
    ClientAnchor clientAnchor=xssfChart.getPreferredSize();
    int width=getXSSFWidthInPx(poiSheet,clientAnchor);
    int height=getXSSFHeightInPx(poiSheet,clientAnchor);
    NViewAnchor viewAnchor=new NViewAnchor(clientAnchor.getRow1(),clientAnchor.getCol1(),width,height);
    NChart chart=null;
    CategoryData categoryData=null;
switch (xssfChart.getChartType()) {
case Area:
      chart=sheet.addChart(NChartType.AREA,viewAnchor);
    categoryData=new XSSFAreaChartData(xssfChart);
  chart.setGrouping(convertGrouping(((XSSFAreaChartData)categoryData).getGrouping()));
break;
case Area3D:
chart=sheet.addChart(NChartType.AREA,viewAnchor);
categoryData=new XSSFArea3DChartData(xssfChart);
chart.setGrouping(convertGrouping(((XSSFArea3DChartData)categoryData).getGrouping()));
break;
case Bar:
chart=sheet.addChart(NChartType.BAR,viewAnchor);
categoryData=new XSSFBarChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFBarChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFBarChartData)categoryData).getGrouping()));
break;
case Bar3D:
chart=sheet.addChart(NChartType.BAR,viewAnchor);
categoryData=new XSSFBar3DChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFBar3DChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFBar3DChartData)categoryData).getGrouping()));
break;
case Bubble:
chart=sheet.addChart(NChartType.BUBBLE,viewAnchor);
XYZData xyzData=new XSSFBubbleChartData(xssfChart);
importXyzSeries(xyzData.getSeries(),chart);
break;
case Column:
chart=sheet.addChart(NChartType.COLUMN,viewAnchor);
categoryData=new XSSFColumnChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFColumnChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFColumnChartData)categoryData).getGrouping()));
break;
case Column3D:
chart=sheet.addChart(NChartType.COLUMN,viewAnchor);
categoryData=new XSSFColumn3DChartData(xssfChart);
chart.setBarDirection(convertBarDirection(((XSSFColumn3DChartData)categoryData).getBarDirection()));
chart.setGrouping(convertGrouping(((XSSFColumn3DChartData)categoryData).getGrouping()));
break;
case Doughnut:
chart=sheet.addChart(NChartType.DOUGHNUT,viewAnchor);
categoryData=new XSSFDoughnutChartData(xssfChart);
break;
case Line:
chart=sheet.addChart(NChartType.LINE,viewAnchor);
categoryData=new XSSFLineChartData(xssfChart);
break;
case Line3D:
chart=sheet.addChart(NChartType.LINE,viewAnchor);
categoryData=new XSSFLine3DChartData(xssfChart);
break;
case Pie:
chart=sheet.addChart(NChartType.PIE,viewAnchor);
categoryData=new XSSFPieChartData(xssfChart);
break;
case Pie3D:
chart=sheet.addChart(NChartType.PIE,viewAnchor);
categoryData=new XSSFPie3DChartData(xssfChart);
break;
case Scatter:
chart=sheet.addChart(NChartType.SCATTER,viewAnchor);
XYData xyData=new XSSFScatChartData(xssfChart);
importXySeries(xyData.getSeries(),chart);
break;
case Stock:
chart=sheet.addChart(NChartType.STOCK,viewAnchor);
categoryData=new XSSFStockChartData(xssfChart);
break;
default :
continue;
}
if (xssfChart.getTitle() != null) {
chart.setTitle(xssfChart.getTitle().getString());
}
chart.setThreeD(xssfChart.isSetView3D());
chart.setLegendPosition(convertLengendPosition(xssfChart.getOrCreateLegend().getPosition()));
if (categoryData != null) {
importSeries(categoryData.getSeries(),chart);
}
}
}