Excel workbook protection

import com.gembox.spreadsheet.*;

class Program {

    public static void main(String[] args) throws java.io.IOException {
        // If using the Professional version, put your serial key below.
        SpreadsheetInfo.setLicense("FREE-LIMITED-KEY");

        ExcelFile workbook = new ExcelFile();
        ExcelWorksheet worksheet = workbook.addWorksheet("Workbook Protection");

        // ProtectionSettings class is supported only for XLSX file format.
        WorkbookProtection protectionSettings = workbook.getProtectionSettings();
        protectionSettings.setProtectStructure(true);

        worksheet.getCell(0, 0).setValue("Workbook password is 123 (only supported for XLSX file format).");
        protectionSettings.setPassword("123");

        workbook.save("Workbook Protection.xlsx");
    }
}