Hey Kunal, Advanced User Interactions API handles the special keyboard and mouse events. It contains the Actions and the Action classes that are needed when executing these events. Following code snippet will allow you to perform Shift keys up and down and also to double click and right click on an element:
public static void main(String[] args) {
WebDriver driver = new FirefoxDriver();
driver.get("https://www.facebook.com");
WebElement txtUsername = driver.findElement(By.id("email"));
Actions builder = new Actions(driver);
Action seriesOfActions = builder
.moveToElement(txtUsername)
.click()
.keyDown(txtUsername, Keys.SHIFT)
.sendKeys(txtUsername, "hello")
.keyUp(txtUsername, Keys.SHIFT)
.doubleClick(txtUsername)
.contextClick()
.build();
seriesOfActions.perform() ;
}