Locating WebElements using CSS

/*********************************

Title  : Locate Element By CSS
Author : Gaurav Khanna

 *********************************/

package com.gaurav.webdriver;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.testng.annotations.Test;

public class LocateByCSS {

    //
    WebDriver webDriver = new FirefoxDriver();

    @Test
    public void testlocateByCSS() throws InterruptedException {

        //
        webDriver.get("http://book.theautomatedtester.co.uk/chapter1");

        //
        WebElement button = webDriver.findElement(By
                .cssSelector("html body div.mainbody p input#radiobutton"));

        //
        button.click();

        //
        Thread.sleep(5000);

        //
        webDriver.quit();

    }

}