When Running Selenium with TestnG I get FAILED CONFIGURATION: BeforeClass setUp?

Question

When I'm trying to run Selenium using TestNg I get Failed Configuration @BeforeClass Error null null. Can you help me?

public class Practice {

 WebDriver driver;

@BeforeClass(alwaysRun = true)
@Parameters({ "browser", "url" })
public void setUp(@Optional String browser, @Optional String url) throws MalformedURLException {
    Selen base = new Selen(browser, url);
    driver = base.getDriver();

}

@Test
public void Check() {
    try {
        System.out.println("Passed Test case...");

        Assert.assertTrue(driver.getTitle().contentEquals("Google"));

        } catch (Exception ee) {
        System.out.println("NOOOOO ");
        ee.printStackTrace();

        Assert.assertEquals("noooo " + ee, "iT SHOULD NOT fAIL");
    }
}

}

public class Selen {

    private WebDriver driver;
    private String browser;
    private String url;


public Selen(String browser, String url) {
    this.browser = browser;
    this.url = url;

    if (browser.equalsIgnoreCase("firefox")) {

        System.setProperty("webdriver.firefox.marionette",
                "C:\\Users\\geckodriver.exe");

        final FirefoxProfile firefox = new FirefoxProfile();


        driver = new FirefoxDriver();

        driver.get(url);

    }

    else if (browser.equalsIgnoreCase("chrome")) {
        // set path to chromedriver.exe
        System.setProperty("webdriver.chrome.driver", "C:\\Drivers\\chromedriver.exe");

        ChromeOptions options = new ChromeOptions();
        options.addArguments("--enable-automation", "test-type=browser", "--disable-plugins", "--disable-infobars",
                "--disable-notifications", "start-maximized");
        driver = new ChromeDriver(options);
        driver.get(url);

    }

    else if (browser.equalsIgnoreCase("Edge")) {
        // set path to Edge.exe
        System.setProperty("webdriver.edge.driver", ".\\MicrosoftWebDriver.exe");

        driver = new EdgeDriver();
        driver.get(url);
    } else {

    }


}

public String getBrowser() {
    return this.browser;
}

public String getBaseUrl() {
    return this.url;
}

public WebDriver getDriver() {
    return this.driver;
}

@AfterClass
public void tearDown(WebDriver driver) {
    quitDriver(driver);
}

protected static void quitDriver(WebDriver driver) {
    try {
        if (driver != null) {
            driver.quit();
        }
    } catch (Exception ee) {
        System.out.println("Failed: " + ee);
        ;
    }
}

}

Failed Configuration

[RemoteTestNG] detected TestNG version 6.14.3
FAILED CONFIGURATION: @BeforeClass setUp(null, null)
java.lang.NullPointerException
    at com.seleniumae.settings.Salen.<init>(Salen.java:34)
    at com.seleniumae.exercise.Practice(Practice.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124)
    at org.testng.internal.MethodInvocationHelper.invokeMethodConsideringTimeout(MethodInvocationHelper.java:59)
    at org.testng.internal.Invoker.invokeConfigurationMethod(Invoker.java:458)
    at org.testng.internal.Invoker.invokeConfigurations(Invoker.java:222)
    at org.testng.internal.Invoker.invokeConfigurations(Invoker.java:142)
    at org.testng.internal.TestMethodWorker.invokeBeforeClassMethods(TestMethodWorker.java:168)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:105)
    at org.testng.TestRunner.privateRun(TestRunner.java:648)
    at org.testng.TestRunner.run(TestRunner.java:505)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:455)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:450)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:415)
    at org.testng.SuiteRunner.run(SuiteRunner.java:364)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:84)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1208)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1137)
    at org.testng.TestNG.runSuites(TestNG.java:1049)
    at org.testng.TestNG.run(TestNG.java:1017)
    at 

   org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:115)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)