I changed the csv format to:

name,purchase,date
TEST,TEST,2018-09-16T08:00:00
TEST,TEST,2018-09-16T08:00:00

I modified the class that binds to the csv to look like this:

public class CsvRecords {
  @CsvBindByName
  private String name;
  @CsvBindByName
  private String purchase;
  @CsvBindByName
  private String date;

  // get and setters left out for brevity pls comment if needed
}

The POJO class for the data in db:

public class Records {
  private String name;
  private String purchase;
  private Timestamp date;

  // get and setters left out for brevity pls comment if needed
}

When uploading in the controller class I then convert the string to LocalDateTime and then again to Timestamp like this:

@PostMapping("/upload-csv-file")
    public String uploadCSVFile(@RequestParam("file") MultipartFile file, Model model) {

        // validate file
        if (file.isEmpty()) {
            model.addAttribute("message", "Please select a CSV file to upload.");
            model.addAttribute("status", false);
        } else {

            // parse CSV file to create a list of `User` objects
            try (Reader reader = new BufferedReader(new InputStreamReader(file.getInputStream()))) {

                // create csv bean reader
                CsvToBean<Records> csvToBean = new CsvToBeanBuilder(reader)
                        .withType(Records.class)
                        .withIgnoreLeadingWhiteSpace(true)
                        .build();

                // convert `CsvToBean` object to list of records
                List<Records> records = csvToBean.parse();

                // save users in DB?
                for(int i = 0; i<records.size(); i++){
                   LocalDateTime localDateTime = LocalDateTime.parse(records.get(i).getDate);
                   Timestamp timestamp = Timestamp.valueOf(localDateTime);
                   Records rec = new Records(records.get(i).getName(), records.get(i).getPurchase(), timestamp)
                   firebaseServices.saveDetails(rec);
                 }
            } catch (Exception ex) {
                model.addAttribute("message", "An error occurred while processing the CSV file.");
                model.addAttribute("status", false);
            }
        }

        return "file-upload-status";
    }

For details on the implementation of the firebaseServices class (saveDetails method) I used this tutorial