Generated excel file from java step from pega using below code,

        try (         XSSFWorkbook workbook = new XSSFWorkbook()) {               FileOutputStream out = new FileOutputStream(new File("createworkbook.xlsx"));               workbook.write(out);               out.flush();               out.close();

 

Ofcourse, I have fixed all errors at compile time with above code to add full class names. The problem is , File is getting generated however, the generated excel file while opening throwing error as "Excel cannot open the file <Filename> because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file."