select a value from drop down in selenium java webdriver using

You can click the drop down and wait for the options to get displayed and then you can click the option from it.

or

Select select = new Select(driver.findElement(By.id("drop_down_id")));

select.selectByIndex(`index_value_of_option`);

Jyotsna... Your script need to wait till the field appear. For this you need to use any of the wait condition.

implicit wait

driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

or sleep condition

Thread.sleep(2000);

or you can use Fluent wait (the best one as per my suggestion)

public WebElement fluentWait(final By locator) {
    Wait<WebDriver> wait = new FluentWait<WebDriver>(driver)
            .withTimeout(30, TimeUnit.SECONDS)
            .pollingEvery(5, TimeUnit.SECONDS)
            .ignoring(NoSuchElementException.class);

    WebElement foo = wait.until(new Function<WebDriver, WebElement>() {
        public WebElement apply(WebDriver driver) {
            return driver.findElement(locator);
        }
    });

    return  foo;
};

fluentWait function returns your found web element. From the documentation on fluentWait: An implementation of the Wait interface that may have its timeout and polling interval configured on the fly. Each FluentWait instance defines the maximum amount of time to wait for a condition, as well as the frequency with which to check the condition. Furthermore, the user may configure the wait to ignore specific types of exceptions whilst waiting, such as NoSuchElementExceptions when searching for an element on the page. Details you can get here

Usage of `fluentWait in your case be the following:

WebElement textbox = fluentWait(By.id("textbox"));

Sample statements to open browser, load URL and select value from dropdown

static WebDriver driver;
System.setProperty("webdriver.ie.driver","C:\\(Path)\\IEDriverServer.exe");
driver = new InternetExplorerDriver();
driver.manage().window().maximize();

driver.get("EnterURLHere");          
driver.manage().timeouts().implicitlyWait(30,TimeUnit.SECONDS);

Select value1 = new Select(driver.findElement(By.id("LocateId")));    
value1.selectByVisibleText("ValueToBeSelected");    //Select Character from dropdown list

you can add wait so that the problem of late loading would be resolve.

driver.manage().timeouts().implicitlyWait(20,TimeUnit.SECONDS);

or,

Thread.sleep(2000);

For selecting from drop down , there are multiple ways from which one can select :

Select dropdown = new Select(driver.findElement(By.id(""))); // By id
dropdown.selectByVisibleText(""); // By Visible text
dropdown.selectByIndex(1); // By index