Java Testing Interview Questions and Answers for Freshers

Java Testing Interview Questions and Answers for Freshers


Java is a versatile, powerful programming language that has been in use for over two decades. Java is used in everything from desktop applications to Android apps and server-side code. Java is also a heavily tested language, which means that if you are looking for a job in the IT field, you are going to need to know how to write Java tests. In this introductory tutorial, we will discuss few basic Java testing interview questions and answers for Freshers as well as Experienced.

Here are some of the most common Java Testing Interview Questions, along with detailed answers that will help you land top Java Testing jobs.

1. What do you know about Framework?

Frameworks are a set of rules that need to be followed systematically to reach a goal. In the Java language, there are so many frameworks available including MVC frameworks to develop applications, build unit test cases, and automate testing.

2. What is the Test Automation Frameworks?

Test Automation Frameworks are frameworks that work with various methods of testing. Some popular test automation frameworks include
Modular Testing Framework.
Keyword Driven Testing Framework.
Hybrid Testing Framework.
Data-Driven Testing Framework.

3. Why did you want to use Framework?

In Test Automation Framework, there are many files that we need to handle. In order to complete all tasks in the framework and achieve our goal successfully, we need to support any framework.

4. What are the main advantages of using Framework?

There are many advantages of using them, among which some are given below: Automation Testing is faster and better than Manual testing. It’s time saving and economical.
In this type of testing there is a higher probability that test results will be obtained after execution of any test cases when compared with manual testing.
it’s more reliable; reusability code is one advantage
We can get automated reports automatically without needing human intervention for tests
Minimal human intervention required by frameworks for their usage.

5. What framework have you used in your Selenium project?

In the Selenium Project, we use Java but there are other languages that can be used. The thing about Java is it’s best to match this language with what you want to do in Selenium because that almost always works out better for different projects and purposes.
For our project, Data-Driven Testing Framework was used as well as Page Factory design pattern which makes it easier to work on multi-page testing scenarios.

6. Explain Java Main Method public static void main (String[] args)

The first method you will encounter in Java is public static void main(). It’s important and the starting point of any Java program. Technically, it is where JVM starts an application at its start up. The main()method should have a signature that specifies how to handle arguments (String [] args).

7. What is Java?

Java has been the preferred programming language of developers for more than two decades because it offers a simple and reliable development platform.

Java’s architecture offers the following features:
Reliable – Runs on all computers that support Java without needing to install special hardware or software. Reliability is one of the main reasons that Java is a preferred programming language for so many developers. Backed by Oracle, which acquired Sun Microsystems in 2010, Java continues to be upgraded and improved with new releases that ensure it remains an industry leader. The current version of Java is version 11, which was released in September 2018.
Secure – In addition to being dependable, Java also has built-in security features that help protect software from hackers and other malicious programmers who might try to take advantage of vulnerabilities in other languages or platforms. This means that you can use the same programming language for both enterprise applications and consumer applications, such as mobile apps and games.

8. Mention some features of Java?

Some of the features which play an important role in the popularity of java are as follows:
Simple: Java is really easy to learn and understand. Java is based on C++ but was created to address some of the coding mistakes found in C++.
Object-Oriented: Java is an object-oriented programming language. Every programming element in Java should be considered as an object.
Portable: Java’s runtime environment uses a bytecode verification process to make sure that code from a remote source doesn’t violate the Java security constraints.
Platform independent: In Java we can create a program and with just one codebase it will work on different platforms without the need to change anything.
Secured: Java is a secure programming language that can help you deal with the threat of viruses.
High Performance: JJIT compilers help create newer versions of Java programs. These versions are compiled into machine-language and executed more quickly than the original version.
Multithreaded: Java’s multithreaded features allow for the development of programs that can function on a variety of tasks simultaneously. A unique but common trait of Java is its use of multithreading, which shares a single memory area. This means that even if there are many parallel threads running at the same time, they will be using only one pool of memory and will not cause any issues with regards to performance.

9. Is Java 100% Object Oriented Language?

Java is not a pure Object-Oriented Language as it supports primitive data types such as byte, Boolean, char, double, float, int, long, short.
Primitive data types do not support object orientation.
Therefore, Java isn’t 100% object-oriented.

10. What do you mean by data encapsulation?

Data encapsulation is the concept of binding data and code into a single unit and hiding the implementation details of a class from the user. It prevents unauthorized access to data and restricts the user to only use necessary information.

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11. What is the difference between Object-oriented programming language and Object-based programming language?

Object-Oriented Languages (OOP) follow all OOP concepts, while Object-Based Languages don’t follow all OOP concepts like inheritance and polymorphism.
There are no inbuilt objects in object-oriented languages, but Object-based languages have inbuilt objects, for example, JavaScript has a window object.

12. What is the difference between Java’s Declaration and Definition?

Function declarations tell the compiler about a function’s name, return type, and parameters.
But a function definition explains what the function does.
The Object Oriented Languages are C#, Java, while Object-based languages are VB etc.

13. What is JRE, and why is it required?

JRE, or Java Runtime Environment, runs on top of the operating system software of a computer and provides the class libraries and other resources that a Java program needs to run.
Java Runtime Environment (JRE) is one of three components required to develop and run Java programs.

14. What is JDK, and why is it required?

JDK stands for Java Development Kit.
JDK is a development environment for developing Java-based applications, applets, and components.
JDK contains tools that are useful for developing and testing Java programs.

15. What is JVM, and why is it required?

JVM stands for Java Virtual Machine
JVMs load, verify, and execute Java bytecode. Because it executes Java programs, it is called the interpreter or the core of Java.

16. What is an Object in Java?

A thing that has state and behavior is called an object, e.g., a chair, bike, marker, pen, table, car, etc. It can be physical or logical (tangible or intangible). For example, the banking system is an intangible object.

17. What is a Class in Java?

A class is a building block in object-oriented programming. As a template, it describes the data and behavior associated with the class instantiation. It is possible to access the member variables and methods of a class by creating an instance of that class (variable).
To create objects with common properties and methods, a class acts as a logical template.
Java provides a reserved keyword class for class definitions. You must follow the keyword with the class name. Methods and variables will be declared inside the class.

18. What is Constructor in Java?


The constructor in Java initializes objects by using a special method.The constructor is called whenever an object of a class is created.

19. What is Local Variable and Instance Variable?

Local variables are visible only to the method or block they were declared, while instance variables are visible to all methods in the class.
Local variables are declared within a method or a block, whereas instance variables are declared within a class, but outside a method.
Existence time: Local variables are created when a method is called and destroyed when the method ends, whereas instance variables are created with new and destroyed by the garbage collector when there are no references to them.
Access: Local variables cannot be accessed, while instance variables can be accessed if they are declared as public.
Local variables are declared in a method or a block before they are called, whereas instance variables can be declared anywhere in the class (even after they have been used).

20. What are the oops concepts?

Java OOps concepts improve reusability and readability of code by defining programs efficiently.
In object-oriented programming, the four basic principles are abstraction, encapsulation, inheritance, and polymorphism. Object-oriented programming aims to implement real-world entities in programs.

21. What is Inheritance in Java?

In OOP, we use inheritance to build new classes from existing ones.
It is known as a subclass (child class or derived class) to create a new class and the existing class from which the child class derives to be referred to as a superclass (parent or base class).

22. What is Polymorphism?

Polymorphism is a core concept of object-oriented programming (OOP), and it describes situations where things appear in several different forms. It is a concept in computer science that describes accessing objects of different types from the same interface. There are different implementations for each type.

23. What are the types of Polymorphism in Java?

In Java, there are two types of polymorphism

  1. Compile time polymorphism (Static binding) – Method overloading
  2. Runtime polymorphism (Dynamic binding) – Method overriding

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24. What is Abstraction in Java?

Abstraction of data is the process of hiding certain details and showing only essential information to the user. Interfaces or abstract classes can be used to achieve abstraction.

25. What is Abstract Class in Java?

Abstract classes are classes that are declared abstract. The class may or may not have abstract methods. It is not possible to instantiate abstract classes, but they can be subclassed.

26. What is Abstract Method?

Abstract methods in Java are declared with the keyword “abstract”.
When declaring an abstract method, the abstract keyword must be enclosed within its name.

27. What is method overloading in Java?

Overloading is a concept that allows multiple methods to have the same name but different parameters to be declared within the same class.

28. What is Interface in Java?

In Java, an interface is a blueprint for a class. Interfaces consist of constants and abstract methods.
Java’s interfaces are mechanisms for achieving abstraction.
Java interfaces can only contain abstract methods, not method bodies. Java interfaces are used to create inheritance and abstraction.
As a result, interfaces can have abstract methods and variables. A method body cannot be present.

29. What is String in Java?

Strings are a sequence of characters widely used in Java programming. The Java programming language defines strings as objects. You can create and manipulate strings using the String class in Java.

30. Difference between Array and Arraylist?

The difference between Array and ArrayList in Java is that an Array is static, while an ArrayList is dynamic. It is not possible to change the size of an array once it has been created, however an ArrayList can resize itself when needed.
Another distinction between ArrayList and Array is that Arrays are part of the Java core language, whereas ArrayLists are members of the Collection framework along with classes such as Vector, Hashtable, HashMap, and LinkedList.

31. Difference between Arraylist and Hashset in Java?

There is a major difference between ArrayList and HashSet in that one is a List implementation, and the other is a Set implementation. All the differences between a List and a Set also apply to this pair.

32. What is Multiple Inheritance?

If a class implements more than one interface, or if an interface extends more than one interface, then this is known as multiple inheritance

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33. In Java, what is the difference between throw and throws?

throw keyword
A throw keyword is used in the program to throw an exception within a function or within a block of code.
Checked exceptions cannot be propagated with throw alone.
An instance comes after the throw keyword.
The throw keyword appears within a method.
It is not possible to throw more than one exception.

throws keyword
The throws keyword is used in a method signature to declare an exception that might be thrown during execution of the code.
Using the throws keyword, the checked exception can be propagated.
After the throws keyword comes class.
The throws keyword appears in the method signature.
Multiple exceptions can be declared, such as public void method() that throws IOException and SQLException.

34. Why Java does not support multiple inheritance through class?

Java does not support multiple inheritance like C++ and Common Lisp. To avoid the ambiguity caused by multiple inheritance, Java does not support it. Diamond is an example of such a problem that occurs in multiple inheritance.

35. What is JDBC?

The Java Database Connection API is made up of Java classes and interfaces.


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