Showing java.lang.NullPointerException at org.testng.internal.MethodInvocationHelper.invokeDataProvider(MethodInvocationHelper.java:150) in Testng
<p>It is showing me error while I am using CSVReader</p>

<pre><code>public class firstclass {
    private static WebDriver driver= new FirefoxDriver();

    @DataProvider(name="readcredentials")
    public Object[][] readcredentials() throws Exception{

        CSVReader readunamepass= new CSVReader(new FileReader("D:/My Projects  New/BSP/Aut/Credentials.csv"));
        List&lt;String[]&gt; list = readunamepass.readAll();  
        Iterator&lt;String[]&gt; readnext = list.iterator();

        while(readnext.hasNext())
        {

            String[] credential = readnext.next();
            System.out.println("" +readnext);
            System.out.println("username"+credential[0]+"password" +credential[1]);
            f(credential[0], credential[1]);

         }
        return null;
    }

    @Test(priority=1, dataProvider="readcredentials")
    public void f(String credential, String credential2) throws Exception {
        getDriver().get("http://192.168.1.111/lms");
        getDriver().findElement(By.id("txtUserId")).sendKeys( credential);
        getDriver().findElement(By.id("txtPwd")).sendKeys(credential2);
        getDriver().findElement(By.id("btnSign")).click();
        //Thread.sleep(100000);
        //System.out.println("This is method");
    }

    public WebDriver getDriver(){

        return driver;

    }
</code></pre>

<p>In this program, @dataprovider is reading uname and password from a csv file and passing it to Test method.
I am not able to provide return type so that I have provided null.Please help
More detail -
I have tried to return object but it is showing me some suggestions. I have tried but showing error in compilation. See image <a href="http://i.stack.imgur.com/H64Ys.png" rel="nofollow">Error image</a></p>

<p><a href="http://i.stack.imgur.com/K00KY.png" rel="nofollow">Stacktrace</a></p>