Introduction: Why Java Is Needed for Automation Testing
In today’s hiring process, most companies start with a Java technical interview questions online test before moving to face-to-face or technical rounds. These online tests assess not just Java syntax, but how well candidates apply Java to automation testing, real-world problem solving, and framework design.
Java is critical for automation testing because it:
- Supports object-oriented programming for reusable test design
- Integrates seamlessly with Selenium WebDriver
- Works with JUnit, TestNG, Maven, Jenkins, CI/CD pipelines
- Handles API testing, database validation, and file handling
- Scales easily for enterprise automation frameworks
Online tests typically include:
- MCQs (theory + output-based)
- Java coding problems
- Automation logic questions
- Scenario-based problem solving
Core Java Topics for Testing (Online Test Focus)
1. Object-Oriented Programming (OOP)
- Encapsulation for reusable automation logic
- Inheritance in base test classes
- Polymorphism with WebDriver
- Abstraction using interfaces
2. Java Collections
- List, Set, Map usage in automation
- HashMap for test data
- Thread-safe collections
3. Multithreading
- Thread vs Runnable
- Parallel execution concepts
- ThreadLocal WebDriver
4. Exception Handling
- Checked vs unchecked exceptions
- Selenium exception handling
- try-catch-finally
5. Java Streams
- filter(), map(), reduce()
- Output-based logic questions
Java Technical Interview Questions Online Test (With Answers)
Core Java – MCQ & Output-Based Questions
1. What is Java?
Java is a platform-independent, object-oriented programming language widely used in automation testing.
2. JVM, JRE, and JDK – difference?
| Component | Purpose |
| JVM | Executes bytecode |
| JRE | JVM + libraries |
| JDK | JRE + development tools |
3. Output of the following code
int a = 10;
int b = 20;
System.out.println(a + b);
Output:
30
4. What is platform independence in Java?
Java code runs on any system with a JVM.
OOP Questions (Frequently Asked Online)
5. What is encapsulation?
Wrapping data and methods together and restricting direct access.
class User {
private String name;
public String getName() {
return name;
}
}
6. Can we achieve multiple inheritance in Java?
Yes, using interfaces.
7. Polymorphism example in Selenium
WebDriver driver = new ChromeDriver();
driver.get(“https://example.com”);
Explanation:
WebDriver reference points to ChromeDriver object at runtime.
Collections – Online Test Questions
8. Output-based question
List<String> list = new ArrayList<>();
list.add(“Java”);
list.add(“Test”);
list.add(“Java”);
System.out.println(list.size());
Output:
3
9. Difference between List and Set?
| List | Set |
| Allows duplicates | No duplicates |
| Ordered | Unordered |
10. HashMap vs Hashtable
| HashMap | Hashtable |
| Not synchronized | Synchronized |
| Allows null | No null |
11. Why HashMap is used in automation testing?
To store key-value based test data dynamically.
Exception Handling – Online Test Focus
12. Checked vs unchecked exceptions?
| Checked | Unchecked |
| Compile-time | Runtime |
| IOException | NullPointerException |
13. Output of the code
try {
int a = 10 / 0;
} catch (Exception e) {
System.out.println(“Exception”);
}
Output:
Exception
Multithreading Questions
14. What is multithreading?
Executing multiple threads simultaneously.
15. Thread vs Runnable
| Thread | Runnable |
| Extends Thread | Implements Runnable |
| Less flexible | More flexible |
Java Streams – Output-Based Questions
List<Integer> nums = Arrays.asList(1,2,3,4);
nums.stream().filter(n -> n % 2 == 0).forEach(System.out::println);
Output:
2
4
Java Coding Questions (Online Test Style)
16. Reverse a String
String s = “Java”;
String rev = “”;
for(int i=s.length()-1;i>=0;i–){
rev += s.charAt(i);
}
System.out.println(rev);
Output:
avaJ
17. Check Palindrome
String s = “madam”;
String rev = new StringBuilder(s).reverse().toString();
System.out.println(s.equals(rev));
Output:
true
18. Find Largest Number in Array
int[] arr = {10,50,30};
int max = arr[0];
for(int n : arr){
if(n > max) max = n;
}
System.out.println(max);
Output:
50
19. Count Duplicate Characters
String s = “automation”;
Map<Character,Integer> map = new HashMap<>();
for(char c : s.toCharArray()){
map.put(c, map.getOrDefault(c,0)+1);
}
System.out.println(map);
Java Selenium Coding Challenges (Online Assessment)
Locators
20. Types of Selenium locators
- ID
- Name
- ClassName
- XPath
- CSS Selector
21. Dynamic XPath
//input[contains(@id,’email’)]
22. Explicit Wait Example
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
wait.until(ExpectedConditions.visibilityOfElementLocated(By.id(“login”)));
23. Launch Browser and Print Title
WebDriver driver = new ChromeDriver();
driver.get(“https://example.com”);
System.out.println(driver.getTitle());
driver.quit();
Real-Time Interview Scenarios (Online Test)
Scenario 1: Page Object Model (POM)
Question: Why POM is used?
Answer:
- Improves maintainability
- Reduces code duplication
- Enhances readability
public class LoginPage {
WebDriver driver;
By username = By.id(“user”);
public LoginPage(WebDriver driver){
this.driver = driver;
}
}
Scenario 2: API + Database Validation
Approach:
- Call API using RestAssured
- Fetch DB data using JDBC
- Compare values using assertions
JUnit Interview Questions (Online Test)
24. What is JUnit?
JUnit is a unit testing framework for Java.
25. Common JUnit annotations
| Annotation | Purpose |
| @Test | Test method |
| @BeforeEach | Runs before test |
| @AfterEach | Runs after test |
26. Assertion example
assertEquals(5, 2 + 3);
TestNG Interview Questions
27. Why TestNG is preferred over JUnit?
- Parallel execution
- DataProvider
- Test dependencies
28. DataProvider example
@DataProvider
public Object[][] data(){
return new Object[][] {{“user”,”pass”}};
}
Selenium + Java + API Practical Example
Response response = RestAssured.get(“/users/1”);
Assert.assertEquals(response.getStatusCode(), 200);
Framework Design Questions (Online Test)
29. What is a Hybrid Framework?
Combination of:
- Page Object Model
- Data-Driven framework
- Keyword-Driven framework
30. CI/CD tools used in automation
- Git
- Maven
- Jenkins
- GitHub Actions
31. Role of Cucumber
- BDD approach
- Business-readable tests
- Feature files + step definitions
Common Mistakes in Java Online Technical Tests
- Ignoring output-based questions
- Weak Core Java fundamentals
- Confusing waits in Selenium
- Overusing Thread.sleep()
- No clarity on framework concepts
1-Page Revision Table / Notes
| Area | Key Focus |
| Core Java | OOP, Collections |
| Coding | Strings, Arrays |
| Selenium | Locators, Waits |
| Testing | JUnit, TestNG |
| Framework | POM, Hybrid |
FAQs – Java Technical Interview Questions Online Test
Q1. Are online Java tests difficult?
No, if fundamentals and logic are strong.
Q2. What type of questions are common?
MCQs, output-based, and small coding programs.
Q3. Is Selenium mandatory in online tests?
Yes, for automation roles.
Q4. How many questions should I practice?
At least 200+ java technical interview questions online test.