Program: 56546
Project: 56546
Buggy source:
/** 
 * Convert CellStyle into NCellStyle
 * @param xssfCellStyle
 */
private NCellStyle importXSSFCellStyle(XSSFCellStyle xssfCellStyle){
  NCellStyle cellStyle=book.createCellStyle(true);
  importedStyle.put(xssfCellStyle.getIndex(),cellStyle);
  cellStyle.setDataFormat(xssfCellStyle.getDataFormatString());
  cellStyle.setWrapText(xssfCellStyle.getWrapText());
  cellStyle.setLocked(xssfCellStyle.getLocked());
  cellStyle.setAlignment(convertAlignment(xssfCellStyle.getAlignmentEnum()));
  cellStyle.setVerticalAlignment(convertVerticalAlignment(xssfCellStyle.getVerticalAlignmentEnum()));
  cellStyle.setFillColor(convertPoiColor(xssfCellStyle.getFillForegroundColorColor(),"String_Node_Str"));
  cellStyle.setBorderLeft(convertBorderType(xssfCellStyle.getBorderLeftEnum()));
  cellStyle.setBorderTop(convertBorderType(xssfCellStyle.getBorderTopEnum()));
  cellStyle.setBorderRight(convertBorderType(xssfCellStyle.getBorderRightEnum()));
  cellStyle.setBorderBottom(convertBorderType(xssfCellStyle.getBorderBottomEnum()));
  cellStyle.setBorderLeftColor(convertPoiColor(xssfCellStyle.getLeftBorderColorColor(),"String_Node_Str"));
  cellStyle.setBorderTopColor(convertPoiColor(xssfCellStyle.getTopBorderColorColor(),"String_Node_Str"));
  cellStyle.setBorderRightColor(convertPoiColor(xssfCellStyle.getRightBorderColorColor(),"String_Node_Str"));
  cellStyle.setBorderBottomColor(convertPoiColor(xssfCellStyle.getBottomBorderColorColor(),"String_Node_Str"));
  cellStyle.setFont(importFont(xssfCellStyle));
  return cellStyle;
}

Fixed version (ground truth):
/** 
 * Convert CellStyle into NCellStyle
 * @param xssfCellStyle
 */
private NCellStyle importXSSFCellStyle(XSSFCellStyle xssfCellStyle){
  NCellStyle cellStyle=null;
  if ((cellStyle=importedStyle.get(xssfCellStyle.getIndex())) == null) {
    cellStyle=book.createCellStyle(true);
    importedStyle.put(xssfCellStyle.getIndex(),cellStyle);
    cellStyle.setDataFormat(xssfCellStyle.getDataFormatString());
    cellStyle.setWrapText(xssfCellStyle.getWrapText());
    cellStyle.setLocked(xssfCellStyle.getLocked());
    cellStyle.setAlignment(convertAlignment(xssfCellStyle.getAlignmentEnum()));
    cellStyle.setVerticalAlignment(convertVerticalAlignment(xssfCellStyle.getVerticalAlignmentEnum()));
    cellStyle.setFillColor(convertPoiColor(xssfCellStyle.getFillForegroundColorColor(),"String_Node_Str"));
    cellStyle.setBorderLeft(convertBorderType(xssfCellStyle.getBorderLeftEnum()));
    cellStyle.setBorderTop(convertBorderType(xssfCellStyle.getBorderTopEnum()));
    cellStyle.setBorderRight(convertBorderType(xssfCellStyle.getBorderRightEnum()));
    cellStyle.setBorderBottom(convertBorderType(xssfCellStyle.getBorderBottomEnum()));
    cellStyle.setBorderLeftColor(convertPoiColor(xssfCellStyle.getLeftBorderColorColor(),"String_Node_Str"));
    cellStyle.setBorderTopColor(convertPoiColor(xssfCellStyle.getTopBorderColorColor(),"String_Node_Str"));
    cellStyle.setBorderRightColor(convertPoiColor(xssfCellStyle.getRightBorderColorColor(),"String_Node_Str"));
    cellStyle.setBorderBottomColor(convertPoiColor(xssfCellStyle.getBottomBorderColorColor(),"String_Node_Str"));
    cellStyle.setHidden(xssfCellStyle.getHidden());
    cellStyle.setFont(importFont(xssfCellStyle));
  }
  return cellStyle;
}