Excel data reading (Apache POI) in Selenium Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Apache POI code snippet reading Excel?

Given the following Java code snippet using Apache POI to read an Excel file, what will be printed to the console?

Selenium Java

FileInputStream fis = new FileInputStream("data.xlsx");
Workbook workbook = WorkbookFactory.create(fis);
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(1);
Cell cell = row.getCell(2);
System.out.println(cell.getStringCellValue());
workbook.close();
fis.close();

A NullPointerException at getCell

B FileNotFoundException

C NumberFormatException

D "TestValue"

💡 Hint

Check the cell type and the row/column indices carefully.

The code reads the first sheet, second row (index 1), third cell (index 2) and prints its string value. Assuming the Excel file has "TestValue" in that cell, it prints it. No exceptions occur if the file exists and cell is string type.

❓ assertion

intermediate

Which assertion correctly verifies the Excel cell value?

You read a cell value from Excel using Apache POI and want to assert it equals "Pass" in a Selenium Java test. Which assertion is correct?

Selenium Java

String actualValue = sheet.getRow(0).getCell(1).getStringCellValue();

A assertTrue(actualValue == "Pass");

B assertEquals("Pass", actualValue);

C assertFalse(actualValue.equals("Pass"));

D assertNull(actualValue);

💡 Hint

Use the correct assertion method for string equality in Java.

assertEquals compares string contents correctly. Using == compares references and may fail. assertFalse and assertNull are incorrect here.

🔧 Debug

advanced

Why does this Apache POI code throw NullPointerException?

This code throws NullPointerException at runtime. What is the most likely cause?

Selenium Java

Workbook wb = WorkbookFactory.create(new FileInputStream("test.xlsx"));
Sheet sh = wb.getSheetAt(0);
Row r = sh.getRow(5);
Cell c = r.getCell(3);
String val = c.getStringCellValue();
System.out.println(val);

A Row 5 does not exist in the sheet, so getRow(5) returns null.

B Cell 3 is numeric, so getStringCellValue() throws NullPointerException.

C WorkbookFactory.create throws NullPointerException if file missing.

D FileInputStream is not closed causing NullPointerException.

💡 Hint

Check which object is null before calling methods on it.

If the row does not exist, getRow returns null. Calling getCell on null causes NullPointerException. Numeric cells cause different exceptions, not NPE.

❓ locator

advanced

Which locator is best to find the Excel file for reading in Selenium Java?

You want to load an Excel file named "data.xlsx" located in the "resources" folder inside your project root. Which code correctly locates the file for Apache POI reading?

A FileInputStream fis = new FileInputStream(System.getProperty("user.dir") + "/resources/data.xlsx");

B FileInputStream fis = new FileInputStream("resources/data.xlsx");

C FileInputStream fis = new FileInputStream("src/resources/data.xlsx");

D FileInputStream fis = new FileInputStream("/resources/data.xlsx");

💡 Hint

Use absolute path based on project root for reliable file access.

Option A uses user.dir system property to get project root and appends relative path, ensuring correct file location regardless of working directory. Others may fail if relative path is incorrect.

❓ framework

expert

How to integrate Apache POI Excel reading in a Selenium TestNG framework for data-driven tests?

Which approach correctly integrates Apache POI to provide test data to a TestNG Selenium test method?

A Hardcode Excel data inside @Test method and ignore Apache POI.

B Read Excel inside @Test method and use static variables to share data across tests.

C Use @DataProvider method that reads Excel with Apache POI and returns Object[][] for test method parameters.

D Use Selenium WebDriver to open Excel file and read cells via UI automation.

💡 Hint

TestNG supports data-driven tests via @DataProvider.

Using @DataProvider to read Excel data with Apache POI and supply it to test methods is the standard and clean approach. Reading inside @Test or hardcoding data is not scalable. Selenium cannot read Excel UI.

Practice

1. What is the main purpose of using Apache POI in Selenium Java testing?

easy

A. To read and write Excel files for test data management

B. To locate web elements on a webpage

C. To execute JavaScript code in the browser

D. To generate HTML reports for test results

Solution

1. Step 1: Understand Apache POI's role

   Apache POI is a library used to handle Microsoft Office files, especially Excel, in Java programs.

2. Step 2: Connect Apache POI with Selenium testing

   In Selenium tests, Apache POI helps read and write Excel files to manage test data efficiently.

3. Final Answer:

   To read and write Excel files for test data management -> Option A

4. Quick Check:

   Apache POI = Excel file handling [OK]

Hint: Apache POI = Excel data handling in Java tests [OK]

Common Mistakes:

• Confusing Apache POI with Selenium WebDriver functions
• Thinking Apache POI is for web element locating
• Assuming Apache POI generates test reports

2. Which of the following is the correct way to open an Excel workbook using Apache POI in Java?

easy

A. Workbook workbook = new Workbook("file.xlsx");

B. Workbook workbook = WorkbookFactory.create(new FileInputStream("file.xlsx"));

C. Workbook workbook = Workbook.open("file.xlsx");

D. Workbook workbook = new FileInputStream("file.xlsx");

Solution

1. Step 1: Identify correct Workbook creation method

   Apache POI uses WorkbookFactory.create(InputStream) to open Excel files safely.

2. Step 2: Check each option's syntax

   Workbook workbook = WorkbookFactory.create(new FileInputStream("file.xlsx")); correctly uses WorkbookFactory.create with FileInputStream. Others are invalid or incorrect constructors.

3. Final Answer:

   Workbook workbook = WorkbookFactory.create(new FileInputStream("file.xlsx")); -> Option B

4. Quick Check:

   Use WorkbookFactory.create with FileInputStream [OK]

Hint: Use WorkbookFactory.create with FileInputStream to open Excel [OK]

Common Mistakes:

• Trying to instantiate Workbook directly
• Using wrong constructors or methods
• Assigning FileInputStream to Workbook variable

3. Given the following code snippet, what will be printed if the Excel cell at row 0, column 1 contains the string "TestData"?

Workbook workbook = WorkbookFactory.create(new FileInputStream("data.xlsx"));
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
Cell cell = row.getCell(1);
System.out.println(cell.getStringCellValue());
workbook.close();

medium

A. TestData

B. null

C. 0

D. Throws NullPointerException

Solution

1. Step 1: Access the correct cell value

   The code accesses row 0, cell 1, which contains the string "TestData".

2. Step 2: Print the string cell value

   Calling getStringCellValue() on that cell returns "TestData", which is printed.

3. Final Answer:

   TestData -> Option A

4. Quick Check:

   Cell value = "TestData" printed [OK]

Hint: getStringCellValue() returns cell text directly [OK]

Common Mistakes:

• Assuming cell is null and causes exception
• Using getNumericCellValue() on string cell
• Confusing row and column indexes

4. Identify the error in the following code snippet that reads an Excel file using Apache POI:

FileInputStream fis = new FileInputStream("data.xlsx");
Workbook workbook = WorkbookFactory.create(fis);
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
Cell cell = row.getCell(0);
System.out.println(cell.getStringCellValue());
// Missing workbook.close()

medium

A. WorkbookFactory.create() cannot accept FileInputStream

B. getSheetAt(0) should be getSheet("Sheet1")

C. FileInputStream should be closed after use

D. getStringCellValue() cannot be called on numeric cells

Solution

1. Step 1: Check resource management

   The code opens FileInputStream but does not close it, which can cause resource leaks.

2. Step 2: Confirm correct usage of WorkbookFactory and methods

   WorkbookFactory.create accepts FileInputStream, getSheetAt(0) is valid, and getStringCellValue() is fine if cell is string.

3. Final Answer:

   FileInputStream should be closed after use -> Option C

4. Quick Check:

   Always close streams to avoid leaks [OK]

Hint: Always close FileInputStream and Workbook after use [OK]

Common Mistakes:

• Forgetting to close FileInputStream
• Assuming WorkbookFactory.create rejects streams
• Confusing sheet access methods

5. You want to read multiple rows from an Excel sheet and store the first column values into a List<String>. Which approach correctly reads all rows except the header row using Apache POI?

hard

A. Use a for loop from 1 to sheet.getPhysicalNumberOfRows(), get each row's cell(1) string value, add to list

B. Use a for loop from 0 to sheet.getLastRowNum(), get each row's cell(0) numeric value, add to list

C. Use a while loop with sheet.getPhysicalNumberOfRows(), get cell(1) string value, add to list

D. Use a for loop from 1 to sheet.getLastRowNum(), get each row's cell(0) string value, add to list

Solution

1. Step 1: Skip header row and loop through rows

   Start loop at 1 to skip header (row 0), loop until sheet.getLastRowNum() to cover all rows.

2. Step 2: Access first column cell and get string value

   Get cell at index 0 (first column), call getStringCellValue(), and add to list.

3. Final Answer:

   Use a for loop from 1 to sheet.getLastRowNum(), get each row's cell(0) string value, add to list -> Option D

4. Quick Check:

   Loop rows from 1, get cell(0) string values [OK]

Hint: Start loop at 1 to skip header, get cell(0) string values [OK]

Common Mistakes:

• Starting loop at 0 and including header
• Using wrong cell index (1 instead of 0)
• Using numeric value for string cells