How to Take Screenshot from Remote Machine in Selenium

import java.io.File;
import java.net.URL;

import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.remote.Augmenter;
import org.openqa.selenium.remote.DesiredCapabilities;
import org.openqa.selenium.remote.RemoteWebDriver;

public class Testing {
    
    public void myTest() throws Exception {
        WebDriver driver = new RemoteWebDriver(
                                new URL("http://localhost:4444/wd/hub"), 
                                DesiredCapabilities.firefox());
        
        driver.get("http://www.google.com");
        
        // RemoteWebDriver does not implement the TakesScreenshot class
        // if the driver does have the Capabilities to take a screenshot
        // then Augmenter will add the TakesScreenshot methods to the instance
        WebDriver augmentedDriver = new Augmenter().augment(driver);
        File screenshot = ((TakesScreenshot)augmentedDriver).
                            getScreenshotAs(OutputType.FILE);
    }
}