Exception Handling in Selenium Webdriver (Types)

What is an Exception?

An exception is an error that happens at the time of execution of a program. While a program runs, the programming language generates an exception that must be handled, otherwise the program crashes.

The exception indicates that, although the event can occur, this type of event happens infrequently. When a method is not able to handle the exception, it is thrown to its caller function. In Java, which drives most Selenium suites, every WebDriver exception is unchecked, so the compiler never forces you to catch it — an unhandled failure surfaces only at run time.

Types of Exceptions in Selenium WebDriver

WebDriverException is the base class of the hierarchy, and every exception below inherits from it. The table lists all 41 exceptions you may meet, together with the condition that raises each one.

Three dominate daily debugging: NoSuchElementException means a wrong XPath or an element that has not rendered, TimeoutException means a wait too short for an AJAX response, and StaleElementReferenceException follows a dynamic re-render.

How to Handle Exceptions in Selenium

Here are the standard constructs for handling exceptions in Selenium WebDriver. Each is plain Java, so it works in any WebDriver script without extra libraries.

Step 1) Try-catch

This method can catch exceptions using a combination of the try and catch keywords. The try command marks the start of the block, and catch is placed at the end of the try block, where it resolves the exception.

try
{
// Code
} catch (Exception e) {
// Code for Handling exception
}

Step 2) Multiple catch blocks

There are various types of exceptions, and a single block of code can raise more than one. Multiple catch blocks let you handle every type separately with its own code. You may use more than two catch blocks, and there is no limit on how many you add.

try
{
//Code
} catch (ExceptionType1 e1) {
//Code for Handling Exception 1
} catch (ExceptionType2 e2) {
//Code for Handling Exception 2
}

Step 3) Throw

When you want to generate an exception, the throw keyword hands it on to be handled at run time. Use throw when you are passing an exception onward instead of resolving it in the current method.

public static void anyFunction() throws Exception{

try {
// write your code here
} catch (Exception b) {
// Do whatever you want to perform 
// Throw the Exception back to the system
throw(b);
}
}

Step 4) Multiple Exceptions

You can mention various exceptions in the throws clause.

public static void anyFunction() throws ExceptionType1, ExceptionType2{

try {
// write your code here
} catch (ExceptionType1 e1) {
// Code to handle exception 1
} catch (ExceptionType2 e2) {
// Code to handle exception 2
}

Step 5) Finally

The finally keyword creates a block beneath the try block. It executes irrespective of whether an exception occurred, which makes it the right place to close a driver or release a file handle.

try {
//Code
} catch (ExceptionType1 e1) {
//Catch block
} catch (ExceptionType2 e2) {
//Catch block
} catch (ExceptionType3 e3) {
//Catch block
} finally {
//The finally block always executes.
}

Methods for Displaying Exception Information

Once an exception is caught, the object itself carries the diagnostic detail. You can use the following methods to display it:

Pair these with a screenshot taken inside the catch block, and a failed run shows both what broke and how the page looked.

FAQs