There are a couple of ways you can accomplish this. If you insist on using XPath to do it, you need to add the context node to the locator, like this:

WebElement parentElement = childElement.findElement(By.xpath("./.."));

Alternatively, you can use the JavascriptExecutor interface, which might be slightly more performant. That would look like this:

// NOTE: broken into separate statements for clarity. Could be done as one statement.
JavascriptExecutor executor = (JavascriptExecutor)driver;
WebElement parentElement = (WebElement)executor.executeScript("return arguments[0].parentNode;", childElement);

Best practice is to do what you originally suggested. Use .findElements() and check for .size != 0, or you can also use my preference, .isEmpty(). You can create a utility function like the below to test if an element exists.

public boolean elementExists(By locator)
{
    return !driver.findElements(locator).isEmpty();
}

You could also build this into a function in your page object.

Use Actions class to perform mouse, keyboard actions on WebElements using WebDriver.

Actions action = new Actions(driver);
WebElement element=driver.findElement(By.linkText("TEST"));

//Double click
action.doubleClick(element).perform();

//Mouse over
action.moveToElement(element).perform();

//Right Click
action.contextClick(element).perform();

FluentWait and WebDriverWait both are the implementations of Wait interface.

The goal to use Fluent WebDriver Explicit Wait and WebDriver Explicit Wait is more or less same. However, in few cases, FluentWait can be more flexible. Since both the classes are the implementations of same Wait interface so more or less both have the same feature except The FluentWait has a feature to accept a predicate or a function as an argument in until method. On the other hand, WebDriverWait accepts only function as an ExpectedCondition in until method which restricts you to use a boolean return only.When you use Predicate in FluentWait, it allows you to return any Object from until method.

Look at here carefully: https://seleniumhq.github.io/selenium/docs/api/java/org/openqa/selenium/support/ui/FluentWait.html#until-com.google.common.base.Predicate-

Examples: A FluentWait having Function as an argument in until with String return:

public void exampleOfFluentWait() {
        WebElement foo = driver.findElement(By.id("foo"));
        new FluentWait<WebElement>(foo)
            .withTimeout(10, TimeUnit.SECONDS)
            .pollingEvery(2, TimeUnit.SECONDS)
                    .until(new Function<WebElement, String>() {
                        @Override
                        public String apply(WebElement element) {
                            return element.getText();
                        }
                    });
    }

The Same FluentWait having Function with Boolean return as an argument in until method.

public void exampleOfFluentWait() {
            WebElement foo = driver.findElement(By.id("foo"));
            new FluentWait<WebElement>(foo)
                .withTimeout(10, TimeUnit.SECONDS)
                .pollingEvery(2, TimeUnit.SECONDS)
                        .until(new Function<WebElement, Boolean>() {
                            @Override
                            public Boolean apply(WebElement element) {
                                return element.getText().contains("foo");
                            }
                        });
        }

One more FluentWait with Predicate.

public void exampleOfFluentWithPredicate() {
    WebElement foo = driver.findElement(By.id("foo"));
    new FluentWait<WebElement>(foo)
        .withTimeout(10, TimeUnit.SECONDS)
        .pollingEvery(100, TimeUnit.MILLISECONDS)
                .until(new Predicate<WebElement>() {
                    @Override
                    public boolean apply(WebElement element) {
                        return element.getText().endsWith("04");
                    }
                });
}

Example of WebDriverWait:

public void exampleOfWebDriverWait() {
        WebElement foo = driver.findElement(By.id("foo"));

        new WebDriverWait(driver, 10)
        .pollingEvery(2, TimeUnit.SECONDS)
        .withTimeout(10, TimeUnit.SECONDS)
        .until(ExpectedConditions.visibilityOf(foo));
    }

For example,

 public class TestSelenium {

    @Test(groups= "SMOKE")
    public void runSelenium() {
        System.out.println("runSelenium()");
    }

    @Test(groups= "Regression")
    public void runSelenium1() {
        System.out.println("runSelenium()1");
    }
}

Now if you want to execute only "SMOKE" group, do like this way.

<suite name="TestAll">
<!-- Run test method on group "selenium" only -->
<test name="selenium">

    <groups>
        <run>
            <include name="SMOKE" />
        </run>
    </groups>

     <classes>
        <class name="com.TestSelenium" />
     </classes>

   </test>

</suite>

For more details, inclusion/exclusion refer this. http://testng.org/doc/documentation-main.html#exclusions.

1. They are tools to help you organize your tests. You can define what you want to run before/after tests, you can group your tests, and reporting on them is made easier.

2. It is usually mentioned with Selenium because Selenium is a common testing tool. The two work together well, but they are completely separate. (Selenium connects you to your browser, TestNG/JUnit organizes the tests)

3. Yes. You should be able to pick them up. They are designed to be fairly easy to learn.

Passing a Capabilities object to the ChromeDriver() constructor is deprecated. One way to use a proxy is this:

String proxy = "127.0.0.1:5000";
ChromeOptions options = new ChromeOptions().addArguments("--proxy-server=http://" + proxy);
WebDriver webDriver = new ChromeDriver(options);

Unfortunately

this is not possible with native Selenium API.

But using Javascript you can:

You can use some javascript support, using Seleniums' JavascriptExecutor.executeScript functionality.

The necessary js code can be found here and here(as proposed by @Mahsum Akbas)

Now here is the Java/Selenium Code that will return you a string in the form of "css-attribute01:value01; css-attribute02:value02;".

Be aware that this will return ALL css-attributes on the element.

WebElement we = driver.findElement(By.tagName("div"));
JavascriptExecutor executor = (JavascriptExecutor)driver;
String script = "var s = '';" +
                "var o = getComputedStyle(arguments[0]);" +
                "for(var i = 0; i < o.length; i++){" +
                "s+=o[i] + ':' + o.getPropertyValue(o[i])+';';}" + 
                "return s;";

System.out.println(executor.executeScript(script, we));

You can change the script according to your needs. For example you could return a string that ONLY has all the values without the attributes. Feel free to change and experiment.

Update

If you would be interested in only the inline-styles of the element, then you can use "native" Selenium as pointed out by @JeffC in the comments:

driver.findElement(By.tagName("div")).getAttribute("style")

BUT!:

This will give you only the "inline styles" and NOT all the css-styles that are applied to an element. If you run both versions after one another and print the results you will see the immense difference.

Ok, after hours and even days of research, I found the solution:

For JDK 9 and above, when defining the pom.xml, you have to exclude that sub-dependency whenever you will use a dependency that contains it. In my case, the cobertura dependency included sun.com:tools.

What I edited in my pom.xml file:

<!-- https://mvnrepository.com/artifact/net.sourceforge.cobertura/cobertura -->
    <dependency>
        <groupId>net.sourceforge.cobertura</groupId>
        <artifactId>cobertura</artifactId>
        <version>2.1.1</version>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>com.sun</groupId>
                <artifactId>tools</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

This seems to be still an open issue for some maven dependencies. Check: issues1 or issues2 or Google search: <dependency_you_are_using> sun tools for more info.