Program: 97631
Project: 97631
Buggy source:
@Override public void writeCellText(Object cellData,int cellIndex) throws IOException {
  if (cellData == null) {
    previousCellIndex=-1;
  }
 else {
    out.write("String_Node_Str");
    if (cellData instanceof Date) {
      out.write("String_Node_Str");
    }
 else     if (applyStyle) {
      applyStyleToCell(cellIndex);
    }
    if (previousCellIndex + 1 != cellIndex) {
      out.write("String_Node_Str" + (cellIndex + 1) + "String_Node_Str");
    }
    previousCellIndex=cellIndex;
    if (cellData instanceof String) {
      String cellDataStr=(String)cellData;
      if (!cellDataStr.equals("String_Node_Str") && cellDataStr.charAt(0) == '=') {
        out.write("String_Node_Str" + cellDataStr + "String_Node_Str");
      }
 else {
        out.write("String_Node_Str");
        if (cellDataStr.equals("String_Node_Str")) {
          out.write(emptyStringRepresentation);
        }
 else {
          if (cellDataStr.length() > 32767) {
            out.write(blobMessage);
          }
 else {
            Xml.writeAsCdata(out,cellDataStr);
          }
        }
        out.write("String_Node_Str");
        if (cellDataStr.length() > 32767) {
          out.write("String_Node_Str");
          Xml.writeAsCdata(out,cellDataStr);
          out.write("String_Node_Str");
        }
      }
    }
 else     if (cellData instanceof Number) {
      Number cellDataNum=(Number)cellData;
      out.write("String_Node_Str");
      Xml.writeAsCdata(out,cellDataNum.toString());
      out.write("String_Node_Str");
    }
 else     if (cellData instanceof Date) {
      Date cellDataDate=(Date)cellData;
      out.write("String_Node_Str");
      String dateString=DateUtil.get(cellDataDate,"String_Node_Str") + "String_Node_Str";
      Xml.writeAsCdata(out,dateString);
      out.write("String_Node_Str");
    }
 else {
      out.write("String_Node_Str");
      Xml.writeAsCdata(out,cellData.toString());
      out.write("String_Node_Str");
    }
    out.write("String_Node_Str");
  }
}

Fixed version (ground truth):
@Override public void writeCellText(Object cellData,int cellIndex) throws IOException {
  if (cellData == null) {
    previousCellIndex=-1;
  }
 else {
    out.write("String_Node_Str");
    if (cellData instanceof Date) {
      out.write("String_Node_Str");
    }
 else     if (applyStyle) {
      applyStyleToCell(cellIndex);
    }
    if (previousCellIndex + 1 != cellIndex) {
      out.write("String_Node_Str" + (cellIndex + 1) + "String_Node_Str");
    }
    previousCellIndex=cellIndex;
    if (cellData instanceof String) {
      String cellDataStr=(String)cellData;
      if (!cellDataStr.equals("String_Node_Str") && cellDataStr.charAt(0) == '=') {
        String value=cellDataStr.replaceAll("String_Node_Str","String_Node_Str");
        out.write("String_Node_Str" + value + "String_Node_Str");
      }
 else {
        out.write("String_Node_Str");
        if (cellDataStr.equals("String_Node_Str")) {
          out.write(emptyStringRepresentation);
        }
 else {
          if (cellDataStr.length() > 32767) {
            out.write(blobMessage);
          }
 else {
            Xml.writeAsCdata(out,cellDataStr);
          }
        }
        out.write("String_Node_Str");
        if (cellDataStr.length() > 32767) {
          out.write("String_Node_Str");
          Xml.writeAsCdata(out,cellDataStr);
          out.write("String_Node_Str");
        }
      }
    }
 else     if (cellData instanceof Number) {
      Number cellDataNum=(Number)cellData;
      out.write("String_Node_Str");
      Xml.writeAsCdata(out,cellDataNum.toString());
      out.write("String_Node_Str");
    }
 else     if (cellData instanceof Date) {
      Date cellDataDate=(Date)cellData;
      out.write("String_Node_Str");
      String dateString=DateUtil.get(cellDataDate,"String_Node_Str") + "String_Node_Str";
      Xml.writeAsCdata(out,dateString);
      out.write("String_Node_Str");
    }
 else {
      out.write("String_Node_Str");
      Xml.writeAsCdata(out,cellData.toString());
      out.write("String_Node_Str");
    }
    out.write("String_Node_Str");
  }
}