Passing String variable between two main classes, passing it into String Array

I am working on java IBAN Validator that should take IBAN numbers from particular Excel column and validate them with output "valid/invalid".

I have the validator itself set up in IBANChecker03.java class. It works just fine when I put any number of IBAN numbers into String[] ibans = {"iban number placed here"}

In my second class, temporarily called "HomeOffice.java", I have all the handeling of the Excel file. It iterates through the raws and takes all the IBANs for me + stores it into "cellvalue" variable.

Now I need to kind of connect these two classes together, which is what I am currently stuck on.

May you please help me how can I now take results from cellvalue and pass it into IBANChecker03.java class in String[] ibans = {""} so that it validates the ibans for me?

What would be the best thing of doing this?

Here is the code:

public class IBANChecker03
{
    private static final String DEFSTRS = ""
        + "AL28 AD24 AT20 AZ28 BE16 BH22 BA20 BR29 BG22 "
        + "HR21 CY28 CZ24 DK18 DO28 EE20 FO18 FI18 FR27 GE22 DE22 GI23 "
        + "GL18 GT28 HU28 IS26 IE22 IL23 IT27 KZ20 KW30 LV21 LB28 LI21 "
        + "LT20 LU20 MK19 MT31 MR27 MU30 MC27 MD24 ME22 NL18 NO15 PK24 "
        + "PS29 PL28 PT25 RO24 SM27 SA24 RS22 SK24 SI19 ES24 SE24 CH21 "
        + "TN24 TR26 AE23 GB22 VG24 GR27 CR21";
    private static final Map<String, Integer> DEFINITIONS = new HashMap<>();

    static
    {
        for (String definition : DEFSTRS.split(""))
            DEFINITIONS.put(definition.substring(0, 2), Integer.parseInt(definition.substring(2)));
    }

    public static void main(String[] args)
        throws FileNotFoundException, IOException, Exception
    {
        String[] ibans = {"IBAN goes here"};

        // HERE I NEED TO PASS Cell Values from HomeOffice.java

        for (String iban : ibans)
            System.out.printf("%s is %s.%n", iban, validateIBAN(iban) ? "valid" : "not valid");
    }

    static boolean validateIBAN(String iban)
    {
        iban = iban.replaceAll("\\s", "").toUpperCase(Locale.ROOT);

        int len = iban.length();
        if (len < 4 || !iban.matches("[0-9A-Z]+") || DEFINITIONS.getOrDefault(iban.substring(0, 2), 0) != len)
            return false;

        iban = iban.substring(4) + iban.substring(0, 4);

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < len; i++)
            sb.append(Character.digit(iban.charAt(i), 36));

        BigInteger bigInt = new BigInteger(sb.toString());
        return bigInt.mod(BigInteger.valueOf(97)).intValue() == 1;
    }
}

public class HomeOffice
{
    public static void main(String[] args)
        throws Exception
    {
        File excelFile = new File("IBNTEST.xlsx");
        FileInputStream fis = new FileInputStream(excelFile);
        XSSFWorkbook workbook = new XSSFWorkbook(fis);
        XSSFSheet sheet = workbook.getSheetAt(0);

        // Here we start iterating through raws and cells
        Iterator<Row> rowIt=sheet.iterator();
        while (rowIt.hasNext()) {
            Row row = rowIt.next();
            Iterator<Cell> cellIterator = row.cellIterator();
            while (cellIterator.hasNext()) {
                Cell cell = cellIterator.next();
                if (cell.getColumnIndex() == 7) { // Choose number of column 
                    System.out.println(cell.toString() + ","); // Print cells
                    String cellvalue = cell.toString();   // This I need to pass into IBANCHECKER03.java
                    // Pass into  String[] ibans = {};

                    //-----------HERE I NEED TO CONNECT TO IBANChecker
                }
                workbook.close();
                fis.close();
            }
        }
    } 
}