org.testng.TestNGException: Cannot instantiate class error occurring at execution time

public class Test{
private WebDriver driver;
private String baseUrl;


@BeforeTest
public void setUp() throws Exception {
    driver = new FirefoxDriver();
    driver.manage().window().maximize();
    baseUrl = "https:gmail.com";
    driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);

}

@Test
public void gmalLogin() throws Exception {
    driver.get(baseUrl");
    driver.findElement(By.id("username")).clear();
    driver.findElement(By.id("username")).sendKeys("sunil.wali");
    driver.findElement(By.id("password")).clear();
    driver.findElement(By.id("password")).sendKeys("Trelleborg@123");
    driver.findElement(By.id("log_in")).click();
    driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
    Thread.sleep(10000);

}


@AfterTest
public void tearDown() throws Exception {
    driver.quit();

    }
}

}

Result: Before execution, window() method is undefined in setup method while TestNG installed successfully in system.

After Execution, Result - org.testng.TestNGException:

Cannot instantiate class Test

    at org.testng.internal.ObjectFactoryImpl.newInstance(ObjectFactoryImpl.java:38)

    at org.testng.internal.ClassHelper.createInstance1(ClassHelper.java:387)

    at org.testng.internal.ClassHelper.createInstance(ClassHelper.java:299)

    at org.testng.internal.ClassImpl.getDefaultInstance(ClassImpl.java:110)

    at org.testng.internal.ClassImpl.getInstances(ClassImpl.java:186)