How to use RoutableHttpClientFactory class of org.openqa.selenium.grid.web package

You will have to download the "Selenium Client & WebDriver Language Bindings" for Java from Selenium Downloads. You can download directly by clicking the link here.

Include all the JAR files that are present in the downloaded ZIP file. To include multiple JARs in Java classpath, you can check the link here.

The selenium-server-standalone JAR is required if you are running your tests locally. Executing the command java -jar selenium-server-standalone-2.48.2.jar will start a Selenium server, which required to launch Selenium tests locally. You need not use it, if you are running tests on BrowserStack.

Would also recommend using an IDE for Java. The most commonly recommended ones are IntelliJ Idea, Eclipse, and Netbeans.

sendkeys method is the problem as per the stack trace.

at org.openqa.selenium.remote.RemoteWebElement.sendKeys(RemoteWebElement.java:121)

Please try Actions class to first focus on the element then send required keys.

Actions actions = new Actions(driver);
actions.moveToElement(element);
actions.click();
actions.sendKeys("SOME DATA");
actions.build().perform();

You have to give your chromeDriver.exe file path instead of taking the path from the URL.

example:

 System.setProperty("webdriver.chrome.driver",
            "C:\\Downloads\\chromedriver.exe");

After inspecting the selenium Python API docs and the source code, I can conclude - there is no such a method. And, there is nothing about it inside the WebDriver specification itself.

To set an attribute, usually a script is executed:

elm = driver.find_element_by_id("myid")
driver.execute_script("arguments[0].setAttribute(arguments[1], arguments[2]);", 
                      elm,  
                      "attr_name",
                      "attr_value")

You can use xpath:

WebElement webElement = driver.findElement(By.cssSelector("ul.x"));
webElement.findElements(By.xpath("./li");

Created testng suite file manually as below:

1. Run once your project from Eclipse
2. Refresh your project
3. Now, “test-output” folder will be created under your project –> unfold the folder
4. Double click the ‘index.html’ file -> It will be opened in the Eclipse Browser window or any other external browser (e.g. IE, Google Chrome, FF, MS Edge etc.)
5. Click on the ‘.xml’ link given on the left panel
6. The test suite XML will get opened on the right-side panel
7. Take a copy of the XML content
8. Right click your project >> New >> File
9. Give name of your test suite file (with .xml extension e.g. testng.xml) and click Finish
10. Paste the content that you copied from the ‘index.html’ and amend your suite file as per your needs

These cases are usually when Firefox & Selenium are a little "out of sync" in terms of compatibility.

You should try two things: update Selenium to the latest one and/or downgrade Firefox. Keeping an eye on the Selenium Release Notes

Yes, it's possible

driver.manage().deleteAllCookies();

Call it right after you are creating the new WebDriver instance.

WebDriver driver = new ChromeDriver();
driver.manage().deleteAllCookies();

You can also delete the cookies one by one

Set<Cookie> allCookies = driver.manage().getCookies();
for (Cookie cookie : allCookies) {
    driver.manage().deleteCookieNamed(cookie.getName());
}

Recently Selenium has launched Selenium 3 and if you are trying to use Firefox latest version then you have to use GeckoDriver:

System.setProperty("webdriver.gecko.driver","G:\\Selenium\\Firefox driver\\geckodriver.exe");
WebDriver driver = new FirefoxDriver();

You can check full documentation from here