当我在Eclipse中使用Java代码在Selenium中获取“空指针异常”时，如何定位问题的确切出处？ [关闭]

//This is Base Class
package base;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class BaseClass 
{
    WebDriver driver;

    public void setup() 
    {
        System.setProperty("WebDriver.chrome.driver", "C:/Users/MY PC/Desktop/Kunal/Selenium/chromedriver.exe");
        driver = new ChromeDriver();
        driver.get("URL");
        driver.manage().window().maximize();
    }
}

//This is Login Class
package pages;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;

public class Login
{
        WebDriver driver;

        By EmailID = By.name("username");
        By Pass = By.id("mat-input-1");

        public Login(WebDriver driver)
        {
            this.driver = driver;
        }

        public void login(String Email, String Password) 
        {
            driver.findElement(EmailID).sendKeys(Email);
            driver.findElement(Pass).sendKeys(Password);
            driver.findElement(By.xpath("/html/body/app-root/app-login-user/div/div/mat-card/div/div[2]/form/div[3]/button/span")).click();
        }

}

//This is Test which I want to run and I am getting 'Null Pointer Exception' as soon as I clicked on 'Run' button of Eclipse
NOTE: I have mentioned valid "EmailID" and "Password" while passing the parameters.
package test;

import org.openqa.selenium.WebDriver;

import base.BaseClass;
import pages.Login;

public class LoginTest extends BaseClass 
{
    static WebDriver driver;

    public static void main(String[] args) 
    {
        try
        {
            Login log = new Login(driver);
            log.login("EmailID", "Password");
        }
        catch(Exception e) 
        { 
            e.printStackTrace();
        }

    }

}

请让我知道我到底在哪里陷入困境...

提前致谢。

问候， 库纳尔