I am getting Null pointer Exception while fetching data from the excel sheet

Code:

public class ContactUsFormTest {
WebDriver driver;
@BeforeMethod
public void run()
{
System.setProperty("webdriver.chrome.driver", "Driver Path");
driver=new ChromeDriver();
driver.get("URL");
driver.manage().deleteAllCookies();
driver.manage().window().maximize();
driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
}
@Test(dataProvider="contactUs")
public void contactUs(String firstname,String preference,String lastname,String email,String text,String phone) throws InterruptedException
{
driver.findElement(By.id("first_name")).sendKeys(firstname);
//drop down handling
Select sel = new Select(driver.findElement(By.id("preference")));
sel.selectByVisibleText(preference);
driver.findElement(By.id("last_name")).sendKeys(lastname);
driver.findElement(By.id("email")).sendKeys(email);
driver.findElement(By.id("textarea")).sendKeys(text);
driver.findElement(By.id("phone")).sendKeys(phone);
Thread.sleep(2000);
driver.findElement(By.name("submit")).click();
Thread.sleep(3000);
//Validation
Assert.assertTrue(driver.getTitle().contains("Successful submission"), "Page title verified-Submission UnSuccessful");
System.out.println("Page title verified-Successful submission");
}
@DataProvider(name="contactUs")
public String[][] formData() throws Exception
{
Thread.sleep(3000);
ExcelDataConfig eData=new ExcelDataConfig("Excel sheet path");
int rows=eData.getRowCount(0);
String[][] data1=new String[rows][6];
for(int i=0;i<rows;i++)
{
data1[i][0]=eData.getData(0, i, 0);//first name
data1[i][1]=eData.getData(0, i, 1);//preference
data1[i][2]=eData.getData(0, i, 2);//last name
data1[i][3]=eData.getData(0, i, 3);//email
data1[i][4]=eData.getData(0, i, 4);//text
data1[i][5]=eData.getData(0, i, 5);//phone
}
return data1;
}

}

I am fetching the data from the excel sheet while performing test I am getting below error.

Error:

[Utils] [ERROR] [Error] java.lang.NullPointerException
at dataDrivenFramework.dataDrivenFramework.ExcelDataConfig.getData(ExcelDataConfig.java:31)
at dataDrivenFramework.dataDrivenFramework.ContactUsFormTest.formData(ContactUsFormTest.java:63)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

Here is ExcelDataConfig class:

public class ExcelDataConfig {
XSSFWorkbook wb;
XSSFSheet sheet1;
//Constructor
public ExcelDataConfig(String excelpath) {
try {
File file=new File(excelpath); 
FileInputStream fis=new FileInputStream(file);
wb=new XSSFWorkbook(fis);
} 
catch (Exception e) {
System.out.println(e.getMessage());
}
}
public String getData(int sheetNumber,int row,int column) {
sheet1=wb.getSheetAt(sheetNumber);
String data=sheet1.getRow(row).getCell(column).getStringCellValue();
return data;
}
public int getRowCount(int sheetIndex)
{
int row=wb.getSheetAt(sheetIndex).getLastRowNum();
row=row+1;
return row;
}

}

I have no clue why I am getting this.

There are many possiblities. The requested sheet may not exist. Or the row. Or the cell. You should add null checks.

public String getData(int sheetNumber,int row,int column) {
sheet1=wb.getSheetAt(sheetNumber);
if (sheet1 == null) {
throw new IllegalArgumentException("Sheet number " + sheetNumber + " does not exist."
}
if (sheet1.getRow(row) == null) {
throw new IllegalArgumentException("Row " + row + " in sheet " + sheetNumber + " does not exist."
}
if (sheet1.getRow(row).getCell(column) == null) {
throw new IllegalArgumentException("Cell " + column + " in sheet " + sheetNumber + " and row " + row + " does not exist."
}
String data=sheet1.getRow(row).getCell(column).getStringCellValue();
return data;
}

Try to learn about NullpointerExceptions and how to fix them.