so, you want to add a cookie?
it can be done by
public void addCookie()
{
driver= new FirefoxDriver();
String URL="http://flipkart.com/";
driver.navigate().to(URL);
//we should pass name and value for cookie as parameters
// In this example we are passing, name=mycookie and value=123456789123
Cookie name = new Cookie("mycookie", "123456789123");
driver.manage().addCookie(name);
// After adding the cookie we will check that by displaying all the cookies.
Set<Cookie> cookiesList = driver.manage().getCookies();
for(Cookie getcookies :cookiesList) {
System.out.println(getcookies );
}
}