Introduction: Why Java Is Critical for Automation Testers with 3 Years Experience
For professionals with around 3 years of experience in automation testing, interview expectations move beyond basics. Interviewers look for strong Core Java knowledge, hands-on Selenium automation, framework design understanding, and real-time problem-solving skills.
At this level, companies expect you to:
- Write clean, reusable Java code
- Design or maintain automation frameworks
- Handle real-world Selenium challenges
- Integrate API, database, and CI/CD
- Explain why you chose a design, not just how
That’s why java interview questions for 3 years experience automation testing focus on practical coding, architecture, and decision-making, not just definitions.
Core Java Topics for Automation Testing (3+ Years Focus)
Interviewers expect depth in the following areas:
1. Object-Oriented Programming (OOP)
- Inheritance and method overriding
- Runtime vs compile-time polymorphism
- Abstraction vs encapsulation
- SOLID principles (basic understanding)
2. Java Collections
- List, Set, Map internal behavior
- When to use HashMap vs LinkedHashMap
- Iteration techniques
- Performance considerations
3. Exception Handling
- Custom exceptions
- Exception propagation
- try-with-resources
4. Multithreading (Practical Basics)
- Thread safety
- Synchronization
- Parallel execution in TestNG
5. Java 8 Features
- Streams and filters
- Lambda expressions
- forEach vs traditional loops
Java Interview Questions for 3 Years Experience Automation Testing (Core Java)
Q1. Why is Core Java important for an automation tester with 3 years experience?
Because automation frameworks, utilities, and test logic are written using Core Java, and maintainability depends on clean Java code.
Q2. Explain JVM, JRE, and JDK.
- JVM → Executes bytecode
- JRE → JVM + libraries
- JDK → JRE + development tools
Q3. What is runtime polymorphism?
Method overriding where method execution depends on object type at runtime.
class Browser {
void open() {
System.out.println(“Opening browser”);
}
}
class Chrome extends Browser {
@Override
void open() {
System.out.println(“Opening Chrome browser”);
}
}
Output
Opening Chrome browser
Q4. Difference between abstraction and encapsulation?
- Abstraction hides implementation
- Encapsulation hides data
Q5. What are SOLID principles?
Guidelines for writing maintainable object-oriented code (Single Responsibility, Open-Closed, etc.).
Q6. ArrayList vs HashSet?
- ArrayList → Allows duplicates, maintains order
- HashSet → No duplicates, no order guarantee
Q7. HashMap vs LinkedHashMap?
- HashMap → Faster, no order
- LinkedHashMap → Maintains insertion order
Q8. Write a HashMap iteration example.
HashMap<String,String> map = new HashMap<>();
map.put(“browser”,”chrome”);
for(Map.Entry<String,String> entry : map.entrySet()){
System.out.println(entry.getKey() + “:” + entry.getValue());
}
Output
browser:chrome
Q9. What is a custom exception?
User-defined exception created for business logic failures.
Q10. Exception propagation example.
void test() throws IOException {
throw new IOException(“File error”);
}
Q11. What is multithreading?
Executing multiple threads simultaneously for better performance.
Q12. Why is Runnable preferred over Thread?
Because Java supports only single inheritance.
Q13. Java 8 Stream real-time example.
List<Integer> nums = Arrays.asList(10,20,30,40);
nums.stream().filter(n -> n > 20).forEach(System.out::println);
Output
30
40
Q14. forEach vs traditional loop?
Streams provide cleaner and more readable code.
Q15. Explain immutability.
Immutable objects cannot be changed after creation (e.g., String).
Selenium Interview Questions for 3 Years Experience
Q16. What challenges have you faced in Selenium?
Dynamic elements, synchronization issues, flaky tests.
Q17. What is Selenium WebDriver?
WebDriver automates browsers by communicating directly with them.
Q18. Implicit vs Explicit wait – which do you prefer?
Explicit wait, because it waits for specific conditions.
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
wait.until(ExpectedConditions.visibilityOf(element));
Q19. How do you handle dynamic XPath?
Use contains() or starts-with() functions.
Q20. How do you handle frames?
Using driver.switchTo().frame().
Q21. How do you handle file upload?
Using sendKeys() with file path.
Q22. How do you capture screenshots?
File src = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
Q23. How do you execute JavaScript?
JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript(“window.scrollBy(0,500)”);
Q24. How do you handle parallel execution?
Using TestNG parallel attribute.
Java Selenium Coding Challenges (3 Years Level)
Q25. Automate login using Page Object Model (POM).
Expected approach
- Page class with locators
- Test class with assertions
Q26. Handle stale element exception.
Re-locate element or apply waits.
Q27. Find broken links.
Check HTTP response codes for <a> tags.
Q28. Scroll until element visible.
Use JavaScriptExecutor.
Real-Time Interview Scenarios (Very Important)
Scenario 1: Page Object Model (POM)
Explain:
- Why POM improves maintainability
- How pages interact with tests
Scenario 2: API + UI Validation
Steps
- Call API using Rest Assured
- Capture response
- Validate UI values against API
Scenario 3: Database Validation
Validate UI data against DB using JDBC.
Scenario 4: CI/CD Integration
Explain how Jenkins triggers automation jobs.
JUnit Interview Questions (3 Years Experience)
Q29. What is JUnit?
A unit testing framework for Java.
Q30. JUnit annotations?
- @Test
- @Before
- @After
TestNG Interview Questions (3 Years Experience)
Q31. Why TestNG over JUnit?
Supports parallel execution, grouping, reporting.
Q32. Important TestNG annotations?
- @BeforeSuite
- @BeforeMethod
- @AfterMethod
Q33. DataProvider example.
@DataProvider
public Object[][] loginData() {
return new Object[][] {
{“user1″,”pass1”},
{“user2″,”pass2”}
};
}
Q34. How do you retry failed tests?
Using TestNG retry analyzer.
Selenium + Java + API Practical Example
Response response = RestAssured.get(“/users”);
System.out.println(response.getStatusCode());
Output
200
Framework Design Questions (3 Years Experience – Must Know)
Q35. What is Hybrid Framework?
Combination of POM + Data-Driven + Keyword-Driven.
Q36. How do you structure an automation framework?
- Base class
- Page classes
- Test classes
- Utilities
- Reports
Q37. What build tools have you used?
Maven or Gradle.
Q38. CI/CD tools experience?
Jenkins, GitHub Actions, Azure DevOps.
Common Mistakes by 3-Year Automation Testers
- Weak Core Java fundamentals
- Poor exception handling
- Overusing Thread.sleep()
- Hard-coded test data
- Not understanding framework design
1-Page Revision Table / Notes
| Area | Focus for 3 Years Experience |
| Core Java | OOP, Collections, Streams |
| Selenium | Waits, Dynamic elements |
| TestNG | Parallel execution |
| Framework | POM, Hybrid |
| API | Rest Assured basics |
| CI/CD | Jenkins pipelines |
FAQs – Java Interview Questions for 3 Years Experience Automation Testing
Q1. What level of Java is expected for 3 years experience?
Strong Core Java with practical automation usage.
Q2. Are coding questions mandatory?
Yes, Java and Selenium coding is expected.
Q3. Is framework design asked at this level?
Yes, interviewers expect framework understanding.
Q4. Is API testing required?
Yes, basic API automation is expected.