How to use driver.quit() when running parallel tests

Question

i am running 4 parallel using testNG and Selenium. My Java file looks like this:

public class SecondNGTest {
    
    public static WebDriver driver;
    public static ChromeOptions chromeOptions;
    
    public static final String USERNAME = PRIVATE";
    public static final String AUTOMATE_KEY = "PRIVATE";
    public static final String URL = "https://" + USERNAME + ":" + AUTOMATE_KEY + "@hub-cloud.browserstack.com/wd/hub";
    
    public static DesiredCapabilities caps;

    @Test    
    public void executSessionOne() throws MalformedURLException{
            //First session of WebDriver
        caps = new DesiredCapabilities();
        caps.setCapability("os", "Windows");
        caps.setCapability("os_version", "10");
        caps.setCapability("browser", "Chrome");
        caps.setCapability("browser_version", "80.0 beta");
        caps.setCapability("browserstack.local", "false");
        caps.setCapability("browserstack.selenium_version", "3.5.2");

        caps.setCapability("name", "selenium test");

        driver = new RemoteWebDriver(new URL(URL), caps);
        chromeOptions = new ChromeOptions();

        String chromeDriverPath = "resources/chromedriver.exe";
        System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
            //Goto guru99 site
            driver.get("http://google.com/");
            
        }
        
    @Test    
        public void executeSessionTwo() throws MalformedURLException{
            //Second session of WebDriver
        caps = new DesiredCapabilities();
        caps.setCapability("os", "Windows");
        caps.setCapability("os_version", "10");
        caps.setCapability("browser", "Chrome");
        caps.setCapability("browser_version", "80.0 beta");
        caps.setCapability("browserstack.local", "false");
        caps.setCapability("browserstack.selenium_version", "3.5.2");

        caps.setCapability("name", "selenium test");

        driver = new RemoteWebDriver(new URL(URL), caps);
        chromeOptions = new ChromeOptions();

        String chromeDriverPath = "resources/chromedriver.exe";
        System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
            //Goto guru99 site
            driver.get("http://youtube.com/");
        
        }
        
    @Test    
        public void executSessionThree() throws MalformedURLException{
            //Third session of WebDriver
        caps = new DesiredCapabilities();
        caps.setCapability("os", "Windows");
        caps.setCapability("os_version", "10");
        caps.setCapability("browser", "Chrome");
        caps.setCapability("browser_version", "80.0 beta");
        caps.setCapability("browserstack.local", "false");
        caps.setCapability("browserstack.selenium_version", "3.5.2");

        caps.setCapability("name", "selenium test");

        driver = new RemoteWebDriver(new URL(URL), caps);
        chromeOptions = new ChromeOptions();

        String chromeDriverPath = "resources/chromedriver.exe";
        System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
            //Goto guru99 site
            driver.get("http://slack.com/");
        
        }    
    
    @Test    
    public void executSessionFour() throws MalformedURLException{
        //Third session of WebDriver
    caps = new DesiredCapabilities();
    caps.setCapability("os", "Windows");
    caps.setCapability("os_version", "10");
    caps.setCapability("browser", "Chrome");
    caps.setCapability("browser_version", "80.0 beta");
    caps.setCapability("browserstack.local", "false");
    caps.setCapability("browserstack.selenium_version", "3.5.2");

    caps.setCapability("name", "selenium test");

    driver = new RemoteWebDriver(new URL(URL), caps);
    chromeOptions = new ChromeOptions();

    String chromeDriverPath = "resources/chromedriver.exe";
    System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
        //Goto guru99 site
        driver.get("http://yahoo.com/");
    
    } 
    
    @AfterTest
    public void browserclose (){
        driver.quit();
        System.out.println("TestCase : Browser was closed");
    }
}

It works as it should by opening up 4 browser windows at once and running the tests but the problem is they never end. The @AfterTest block is only being triggered once, so one of the windows does close but the rest are left open and I have to manually close them. How can I close/quit each driver when each test is done?

EDIT: here is my testng.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd" >
<suite name="TestSuite"  >
<test name="testGuru" thread-count="4" parallel="methods">
<classes>
<class name="selerixautomation.SecondNGTest">
</class>
</classes>
</test>
</suite>

Answer 1

Since you are doing your parallel execution inside one java class but different methods (e.g. one @Test annotation one method) you need to call @AfterMethod hook to close all drivers (after every method / @Test annotation method).