How to click on a Dropdown menu through Selenium - selenium

Question

Actions a= new Actions(driver);
WebElement mainmenu=driver.findElement(By.xpath(".//*[#id='yui-gen2']/a"));
a.moveToElement(mainmenu).build().perform();
WebElement Sub = driver.findElement(By.xpath(".//*[#id='helpAbout']"));
a.moveToElement(Sub).build().perform();
Sub.click();
Code couldn't able to click on submenu it just stops at 3rd line.

Answer 1

With selenium you should be able to just do the following:
Select variableName = new Select(DropDownElementLocator);
variableName.selectByVisibleText("Whatever");
// or
variableName.selectByIndex(1);

Answer 2

Your code is 90% correct, just replace following code:
a.moveToElement(Sub).click().perform();
build() method works for hover on element,and after hover on it we have to click element.

Answer 3

Once you Mouse Hover over the element identified as By.xpath(".//*[#id='yui-gen2']/a") and therefafter invoke moveToElement(mainmenu), build(), perform(), at this stage the element identified as By.xpath(".//*[#id='helpAbout']") is visible and interactable. So you need to invoke click() directly as follows :
Actions a= new Actions(driver);
WebElement mainmenu=driver.findElement(By.xpath(".//*[#id='yui-gen2']/a"));
a.moveToElement(mainmenu).build().perform();
WebElement Sub = driver.findElement(By.xpath(".//*[#id='helpAbout']"));
Sub.click();

Answer 4

import org.openqa.selenium.support.ui.Select;
WebElement selectElement;
selectElement= driver.findElement(By.id("yourElementId"));
or
selectElement driver.findElement(By.xpath("yourElementXpath"));
Select selectObject = new Select(selectElement);
The Select object will now give you a series of commands that allow you to interact with a element. First of all, there are different ways of selecting an option from the element.
<select>
<option value=value1>Bread</option>
<option value=value2 selected>Milk</option>
<option value=value3>Cheese</option>
</select>
// Select an <option> based upon the <select> element's internal index
selectObject.selectByIndex(1);
// Select an <option> based upon its value attribute
selectObject.selectByValue("value1");
// Select an <option> based upon its text. Example: Bread
selectObject.selectByVisibleText("Bread");