How to open a new blank window using webdriver in java.

I am using (Webdriver) driver.close(to close the browser instead of using driver.quit). After the browser window is closed i am not able to use driver.get(url) -which throws unreachableBrowserException.

As a work around i am trying to get windowHandles.size(), when it is zero i want to open a new blank window and then use driver.get(url).

But i cound'not find any methods to open a blank window in Webdriver class.