Given a XSSF Sheet.
Then the following code leads to a out.xlsx in which conditional formatting does not work for the created cell A1 (at least not in Excel):


XSSFWorkbook wbOut = new XSSFWorkbook("C:/out.xlsx");
XSSFWorkbook wbIn = new XSSFWorkbook("C:/in.xlsx");

XSSFSheet srcSheet = wbOut.getSheetAt(0);
XSSFSheet dstSheet = wbIn.getSheetAt(0);

XSSFRow srcRow = srcSheet.getRow(0);
XSSFRow dstRow = dstSheet.getRow(0);

XSSFCell oldCell = srcRow.getCell(0);
XSSFCell newCell = dstRow.createCell(0);

Map<String, Object> props = new HashMap<>();
props.put(CellUtil.ROTATION, oldCell.getCellStyle().getRotation());
CellUtil.setCellStyleProperties(newCell, props);


The problem is similar to the one in bug 60845, setCellStyleProperties() creates new fills instead of using the already existing ones:

That means, the corresponding Fill for A1 is now:

<fill>
  <patternFill>
    <fgColor indexed="64"/>
    <bgColor indexed="64"/>
  </patternFill>
</fill>

instead of the default one:

<fill>
  <patternFill patternType="none"/>
</fill>

---

A possible solution could be:
1) handle "indexed="64" as "none"/null, since 64 is the value for AUTOMATIC/NONE in the getFormatProperties/setFormatProperties functions
2) create a new derived CellUtil for XSSF, since many other things (like XSSFColors) don't work too