findElement by ID in Selenium Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the findElement(By.id()) method do in Selenium?

It locates the first web element on the page that matches the given ID attribute value.

beginner

Why is using ID as a locator preferred in Selenium tests?

Because IDs are unique on a page, locating elements by ID is fast and reliable.

beginner

Show a simple Java code snippet to find a button with ID 'submitBtn' and click it.

WebElement button = driver.findElement(By.id("submitBtn")); button.click();

intermediate

What happens if findElement(By.id()) does not find any matching element?

It throws a NoSuchElementException, causing the test to fail unless handled.

intermediate

How can you improve test stability when using findElement(By.id())?

Use explicit waits to wait until the element is present and visible before interacting with it.

What does driver.findElement(By.id("username")) return?

A A list of elements with ID 'username'

B All elements with ID 'username'

C Null if no element found

D The first element with ID 'username'

findElement returns the first matching element or throws an exception if none found.

Which exception is thrown if findElement(By.id()) finds no element?

A TimeoutException

B NoSuchElementException

C ElementNotVisibleException

D NullPointerException

NoSuchElementException is thrown when no matching element is found.

Why is locating elements by ID faster than by XPath?

A ID locators use CSS selectors internally

B XPath is deprecated

C IDs are unique and browsers optimize ID lookups

D XPath requires JavaScript execution

Browsers optimize locating elements by unique IDs, making it faster.

Which of these is the correct way to find an element by ID 'email' in Selenium Java?

A driver.findElement(By.id("email"));

B driver.findElement(By.name("email"));

C driver.findElement(By.className("email"));

D driver.findElement(By.tagName("email"));

By.id("email") locates element by its ID attribute.

What should you do before clicking an element found by ID to avoid errors?

A Wait until the element is visible and clickable

B Immediately click without waiting

C Refresh the page

D Clear browser cache

Waiting ensures the element is ready for interaction, preventing errors.

Explain how to use findElement(By.id()) in Selenium Java and what to watch out for.

Think about locating elements uniquely and handling missing elements.

Describe why using ID as a locator is recommended and how it affects test speed and reliability.

Consider how browsers find elements and how that impacts tests.

Practice

1. What does the Selenium method findElement(By.id("submitBtn")) do?

easy

A. Finds elements by their tag name "submitBtn".

B. Finds the first element on the page with the ID "submitBtn".

C. Finds elements by their class name "submitBtn".

D. Finds all elements with the ID "submitBtn".

Solution

1. Step 1: Understand the method purpose

   The method findElement locates a single web element on the page.

2. Step 2: Analyze the locator used

   Using By.id("submitBtn") means it looks for an element with the exact ID "submitBtn".

3. Final Answer:

   Finds the first element on the page with the ID "submitBtn". -> Option B

4. Quick Check:

   findElement + By.id = single element by ID [OK]

Hint: findElement(By.id) always returns one element by unique ID [OK]

Common Mistakes:

• Confusing findElement with findElements (plural)
• Using class name or tag name instead of ID
• Assuming it returns multiple elements

2. Which of the following is the correct syntax to find an element with ID "username" in Selenium Java?

easy

A. driver.findElement(By.id="username");

B. driver.findElement(By.Id("username"));

C. driver.findElement(By.ID("username"));

D. driver.findElement(By.id("username"));

Solution

1. Step 1: Recall correct method syntax

   The method By.id is called with parentheses and a string argument, like By.id("username").

2. Step 2: Check Java case sensitivity

   Java is case-sensitive, so By.id must be lowercase 'id', and parentheses are required.

3. Final Answer:

   driver.findElement(By.id("username")); -> Option D

4. Quick Check:

   Correct method call syntax = driver.findElement(By.id("username")); [OK]

Hint: Use By.id("value") with parentheses and lowercase 'id' [OK]

Common Mistakes:

• Using assignment '=' instead of parentheses
• Wrong capitalization like By.ID or By.Id
• Missing parentheses around the ID string

3. What will happen when the following code runs if no element with ID "loginBtn" exists on the page?

WebElement button = driver.findElement(By.id("loginBtn"));
button.click();

medium

A. Throws NoSuchElementException at findElement line.

B. Throws NullPointerException at button.click().

C. The code clicks the button successfully.

D. Returns null and skips the click.

Solution

1. Step 1: Understand findElement behavior when element missing

   If no element matches the ID, findElement throws NoSuchElementException immediately.

2. Step 2: Analyze code flow

   The exception occurs at the findElement line, so button.click() is never reached.

3. Final Answer:

   Throws NoSuchElementException at findElement line. -> Option A

4. Quick Check:

   Missing element causes NoSuchElementException [OK]

Hint: findElement throws exception if ID not found, no null returned [OK]

Common Mistakes:

• Assuming findElement returns null if element missing
• Expecting NullPointerException instead
• Thinking click() runs even if element not found

4. Identify the error in this Selenium Java code snippet:

WebElement input = driver.findElement(By.id("email"));
input.sendKeys("[e-mail]");
WebElement submit = driver.findElement(By.id("submit"));
submit.click();

Assuming the page has no element with ID "submit".

medium

A. Throws ElementNotInteractableException at sendKeys line.

B. No error; code runs fine.

C. Throws NoSuchElementException at finding "submit" element.

D. Throws StaleElementReferenceException at click line.

Solution

1. Step 1: Check element existence for each findElement

   The element with ID "email" exists, so sendKeys works fine.

2. Step 2: Analyze finding "submit" element

   Since "submit" ID does not exist, findElement(By.id("submit")) throws NoSuchElementException.

3. Final Answer:

   Throws NoSuchElementException at finding "submit" element. -> Option C

4. Quick Check:

   Missing ID causes NoSuchElementException [OK]

Hint: Missing ID in findElement causes NoSuchElementException [OK]

Common Mistakes:

• Assuming sendKeys fails if element missing later
• Confusing exceptions thrown at different lines
• Expecting click() to throw error instead of findElement

5. You want to fill a form field with ID "userEmail" and then click a button with ID "submitBtn". Which code snippet correctly handles the possibility that the button might not be present, avoiding test failure?

hard

A. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]");
try {
driver.findElement(By.id("submitBtn")).click();
} catch (NoSuchElementException e) {
System.out.println("Button not found, skipping click.");
}

B. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]");
WebElement btn = driver.findElement(By.id("submitBtn"));
if(btn != null) {
btn.click();
}

C. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]");
driver.findElement(By.id("submitBtn")).click();

D. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]");
WebElement btn = null;
btn.click();

Solution

1. Step 1: Understand the problem

   The button with ID "submitBtn" might not exist, so clicking it directly may cause an exception.

2. Step 2: Evaluate each option

   driver.findElement(By.id("userEmail")).sendKeys("[e-mail]"); driver.findElement(By.id("submitBtn")).click(); clicks without checking, risking failure. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]"); WebElement btn = driver.findElement(By.id("submitBtn")); if(btn != null) { btn.click(); } attempts null check but throws NoSuchElementException at findElement since it never returns null. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]"); try { driver.findElement(By.id("submitBtn")).click(); } catch (NoSuchElementException e) { System.out.println("Button not found, skipping click."); } uses try-catch to handle missing button gracefully. driver.findElement(By.id("userEmail")).sendKeys("[e-mail]"); WebElement btn = null; btn.click(); assigns null and calls click(), causing NullPointerException.

3. Final Answer:

   Use try-catch to handle missing element and avoid failure. -> Option A

4. Quick Check:

   Try-catch handles missing element safely [OK]

Hint: Use try-catch to handle missing elements safely [OK]

Common Mistakes:

• Not handling missing elements causing test failure
• Calling click() on null element
• Assuming findElement returns null if element is missing