Reusable ExcelUtils Class

package com.practice.utils;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Reusable Excel utility. Every DataProvider in the project
 * calls this instead of writing its own POI code.
 */
public class ExcelUtils {

    /**
     * Reads all data rows from a named sheet.
     * Row 0 is treated as header and skipped.
     *
     * @param filePath  path to .xlsx file
     * @param sheetName name of the sheet tab
     * @return Object[][] ready for TestNG DataProvider
     */
    public static Object[][] readSheet(String filePath,
                                        String sheetName)
            throws IOException {

        List<Object[]> data = new ArrayList<>();

        try (FileInputStream fis = new FileInputStream(filePath);
             Workbook workbook = new XSSFWorkbook(fis)) {

            Sheet sheet = workbook.getSheet(sheetName);
            if (sheet == null) {
                throw new RuntimeException(
                    "Sheet '" + sheetName
                    + "' not found in " + filePath);
            }

            // Get column count from header row
            Row headerRow = sheet.getRow(0);
            if (headerRow == null) {
                throw new RuntimeException(
                    "Header row is empty in sheet: "
                    + sheetName);
            }
            int columnCount = headerRow.getLastCellNum();

            // Read data rows (skip header at index 0)
            for (int i = 1; i <= sheet.getLastRowNum(); i++) {
                Row row = sheet.getRow(i);
                if (row == null) continue;

                Object[] rowData = new Object[columnCount];
                for (int j = 0; j < columnCount; j++) {
                    rowData[j] = getCellValue(row.getCell(j));
                }
                data.add(rowData);
            }
        }

        return data.toArray(new Object[0][]);
    }

    /**
     * Reads the first sheet when you do not care about
     * the sheet name.
     */
    public static Object[][] readFirstSheet(String filePath)
            throws IOException {

        try (FileInputStream fis = new FileInputStream(filePath);
             Workbook workbook = new XSSFWorkbook(fis)) {

            String firstSheetName =
                workbook.getSheetAt(0).getSheetName();
            return readSheet(filePath, firstSheetName);
        }
    }

    /**
     * Gets the number of data rows (excluding header).
     */
    public static int getRowCount(String filePath,
                                   String sheetName)
            throws IOException {

        try (FileInputStream fis = new FileInputStream(filePath);
             Workbook workbook = new XSSFWorkbook(fis)) {

            Sheet sheet = workbook.getSheet(sheetName);
            if (sheet == null) return 0;
            return sheet.getLastRowNum(); // header is row 0
        }
    }

    /**
     * Safely extracts a String value from any cell type.
     * Handles null, STRING, NUMERIC, BOOLEAN, FORMULA,
     * BLANK, and date-formatted cells.
     */
    private static String getCellValue(Cell cell) {
        if (cell == null) return "";

        return switch (cell.getCellType()) {
            case STRING -> cell.getStringCellValue().trim();
            case NUMERIC -> {
                if (DateUtil.isCellDateFormatted(cell)) {
                    yield cell.getDateCellValue().toString();
                }
                double num = cell.getNumericCellValue();
                if (num == Math.floor(num)) {
                    yield String.valueOf((long) num);
                }
                yield String.valueOf(num);
            }
            case BOOLEAN -> String.valueOf(
                cell.getBooleanCellValue());
            case FORMULA -> {
                try {
                    yield cell.getStringCellValue();
                } catch (IllegalStateException e) {
                    yield String.valueOf(
                        cell.getNumericCellValue());
                }
            }
            case BLANK -> "";
            default -> "";
        };
    }
}

import com.practice.utils.ExcelUtils;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
import org.testng.Assert;

public class InsuranceQuoteTest extends BaseTest {

    private static final String DATA_FILE =
        "src/test/resources/test-data/insurance-data.xlsx";

    @DataProvider(name = "quoteData")
    public Object[][] quoteData() throws Exception {
        return ExcelUtils.readSheet(DATA_FILE, "QuoteScenarios");
    }

    @Test(dataProvider = "quoteData")
    public void testInsuranceQuote(String name, String age,
                                    String coverage,
                                    String expectedPremium) {
        navigateTo("/insurance");
        QuotePage quote = new QuotePage(driver);
        quote.enterName(name);
        quote.enterAge(age);
        quote.selectCoverage(coverage);
        quote.clickGetQuote();

        Assert.assertEquals(
            quote.getDisplayedPremium(), expectedPremium,
            "Premium mismatch for: " + name
            + ", age=" + age
            + ", coverage=" + coverage);
    }
}