Drag and Drop element

import java.util.concurrent.TimeUnit;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.interactions.Actions;

public class Dropdrag {
    public static void main(String[] args) {
        WebDriver driver = new FirefoxDriver();
        driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
        driver.get("http://yuiblog.com/sandbox/yui/3.2.0pr1/examples/dd/groups-drag_clean.html");
        Actions act = new Actions(driver);
        WebElement source1 = driver.findElement(By.id("pt1"));
        WebElement target1 = driver.findElement(By.id("t2"));
        act.dragAndDrop(source1,target1).perform();
    }
}