java - How to check a radio button with Selenium WebDriver? -

i want check radio button, didn't know how. html is:

<div class="appendcontent">      <div> id="contentcontainer" class="grid_list_template">         <div id="routemonitoroptions"></div>     </div>      <input id="optionstopgrid" type="radio" name="gridselector"/>     <label for="optionstopgrid">paradas</label> </div> 

    import java.util.list;     import org.openqa.selenium.by;     import org.openqa.selenium.webdriver;     import org.openqa.selenium.webelement;     import org.openqa.selenium.firefox.firefoxdriver;     public class answer {     public static void main(string[] args) throws interruptedexception {     webdriver driver = new firefoxdriver();     driver.get("http://www.example.com/");     //if u want know number of radio buttons use list     list<webelement>radiobutton = driver.findelements(by.tagname("example"));     system.out.println(radiobutton.size());     //if u want select radio button     driver.findelement(by.id("example")).click();     thread.sleep(3000);     //if u want text in u r console     for(int i=0;i<radiobutton.size();i++){     system.out.println(radiobutton.get(i).gettext());     }      //if u want check whether radio button selected or not     if(driver.findelement(by.id("example")).isselected()){         system.out.println("true");     }else     {         system.out.println("false");     }   } }