100 Java Interview Questions For Freshers With Example Answers

By Indeed Editorial Team

Updated 31 October 2022

Published 27 July 2021

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

If you are starting your first job using Java, it can help to prepare for your interview ahead of time. One way to do this is to review possible interview questions in advance. Anticipating questions an interviewer might ask you about Java can help you feel more confident and possibly increase your chances of success. In this article, we discuss Java interview questions for freshers and provide 100 examples and sample answers to help you prepare for your next interview.

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Java Interview Questions For Freshers, An Interviewer May Ask

Interview questions for early-career, Java developers often focus on technical skills and knowledge, so it can help to review your understanding of this programming language and its applications. To help you prepare, here are some questions about Java an interviewer may ask a fresher:

What is Java?

Interviewers ask this question to gauge your basic familiarity with the Java language. Summarise your understanding of Java clearly to show you are comfortable with it.

Example answer: "Java is a programming language that is primarily used for internet applications. It is one of the most commonly used and is platform-independent, meaning you can develop it on one machine and use it on another."

What is a Java platform and how is it different from other platforms?

Interviewer may ask this question to help determine how well you understand the structure of the Java programming language and its relationship to the Java platform and others. Focus on the differences between software and hardware platforms and the way Java fits into this structure to clarify your understanding.

Example answer: "A Java platform is the environment where you develop software using Java. This can include the Standard Edition, Enterprise Edition and Micro Edition Java Platform. A specific Java platform differs from other platforms in that it is intended for the development of Java applications in particular. It is possible to develop using Java on other platforms as well."

What is the difference between Java and other programming languages such as C++?

Interviewers ask questions like this to help them understand your comfort level with Java in the context of other programming languages and systems. This can be especially relevant if they expect the person they hire to use multiple programming languages.

Example answer: "Java differs from other programming languages such as C++ in many ways. For instance, Java is platform-independent, while other languages such as C++ are not. Java is used for building applications, whereas C++ is used for system programming. Other areas of difference include thread support, the virtual keyboard and proximity to hardware. Knowing these differences helps me use Java more effectively."

What are your favourite features of Java?

Your interviewer might ask this question to ensure you have a strong understanding of each feature of Java, especially those that differentiate it from other programming languages. Use this question as an opportunity to showcase your familiarity with Java.

Example answer: "I appreciate the simplicity of the Java platform. I also like that Java is an object-oriented programming system and that it is platform-independent. Java's high level of performance and speech also makes it one of my favourite programming languages and platforms for certain purposes.

What is a Java virtual machine?

This question can tell your interviewer about your familiarity with the relationship between Java and hardware. Clearly explain your understanding of a virtual machine when you answer this question.

Example answer: "If you have a computer that does not run Java, you can use a virtual machine to run the Java program. This specification compiles Java code to Bytecode, which is closer to the computer's code."

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Other Java Interview Questions For Freshers

Here are some additional Java interview questions you might expect as a fresher:

General Java interview questions for freshers

Your interviewer might ask you general questions about Java and its use during your interview for a fresher role. Here are some:

  • Explain wrapper classes in Java.

  • What is autoboxing?

  • What is unboxing?

  • Explain the advantages of object cloning.

  • Describe the disadvantages of object cloning.

  • What is the strictfp keyword and why is it important?

  • Explain the importance of the System class.

  • Describe the singleton class.

  • Explain peerless components.

  • What is a scrollbar?

  • What is a ScrollPane?

  • What is the difference between a heavyweight and lightweight component?

  • What is the difference between an application and an applet?

  • Explain how to use one Java class as an application and an applet.

Java object-oriented programming (OOP) interview questions

Your interviewer may ask you these questions about the object-oriented programming paradigm and Java:

  • What is object-oriented programming?

  • Explain the definition of an object in OOP.

  • What is a constructor in OOP?

  • What is a default constructor in Java?

  • What is a parametrised constructor in Java?

  • Explain the importance of a default constructor.

  • How can you overload a constructor?

  • Describe the initial value of an instance variable object reference.

  • Explain the difference between methods and constructors in Java.

  • Explain the static variable.

  • Describe the static method and its restrictions.

  • Explain the difference between the static method and the instance method.

  • How do you use the "this" keyword in Java?

  • Describe constructor chaining using the "this" keyword in Java.

  • Explain the Inheritance and its use in Java.

  • What is a superclass, and what is the Java superclass?

  • Define aggregation and its importance in Java.

  • Explain the difference between composition and aggregation in Java.

  • What is the "super" keyword and how is it used in Java?

  • Explain method overloading in Java.

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Java Exception Handling Interview Questions

You may be required to answer questions about how you handle exceptions. Here are some examples:

  • What types of exceptions can occur in a Java program?

  • Explain exception handling and the hierarchy of exception classes in Java.

  • What are checked and unchecked exemptions?

  • Is there a difference between "throw" and "throws?" Explain.

  • Describe a Java nested class.

  • Discuss the definition of a nested interface.

  • Explain exception propagation.

  • Explain a "finally" block.

  • What are the advantages of using string pool?

  • Explain how to use a string literal and a new keyword to create a string object.

  • What are the differences between String, StringBuffer and StringBuilder?

  • Describe the process of creating an immutable class.

  • Explain the types of inner classes used in Java.

  • Explain the difference between nested classes and inner classes.

  • Explain the difference between metacharacters and ordinary characters in Java.

Java input and output stream (I/O) interview questions

Your interviewer may ask you I/O questions to explore your Java expertise. Here are a few:

  • What is the difference between an input stream and an output stream in Java?

  • Explain the Reader/Writer class hierarchy and the Input/Output stream hierarchy.

  • When would you use BufferedInputStream and BufferedOutputStream?

  • Describe the process of using the FilePermission class in Java.

  • Explain the use of an I/O filter.

  • How do you use the Scanner class to take input in Java?

  • How do you use BufferedReader to take input in Java?

  • How do you use the Console class to take input in Java?

Java garbage collection interview questions

Here are some questions your interviewer may ask you about garbage collection in Java:

  • Explain garbage collection in Java.

  • How do you use garbage collection for cleanup processing?

  • Can an object be unreferenced? Explain.

  • How do you reference an unreferened object?

  • Explain the Runtime class.

  • What is the relationship between the finalise method and garbage collection?

Java serialisation interview questions

Here are some examples of sterilisation questions you may require to answer:

  • Explain serialisation in Java.

  • Explain deserialisation in Java.

  • Is it possible to prevent child class serialisation in Java? Explain.

  • Explain the differences between serialisable and externalisable interfaces.

Java reflection interview questions

Here are some questions you may answer about reflection in Java during your next interview:

  • Explain reflection in Java.

  • How do you use forName() to instantiate the Class class in Java?

  • How do you use getClass() to instantiate the Class class in Java?

  • How do you use .class syntax to instantiate the Class class in Java?

  • Explain the purpose of javap.

  • What does the java.lang.Class class do?

Java networking interview questions

You might be asked about networking. Some of those questions include:

  • What is Java socket programming?

  • Explain the process of connecting two computers using TCP

  • How can you use Java to connect a client and a server?

  • Describe the process for converting an IP address to a hostname.

Java data structure interview questions

Interviewers commonly ask about data structures in Java. Here are some you may expect:

  • Explain bubble sort in Java.

  • What is binary search in Java?

  • What is Java selection sort?

  • Explain linear search in Java.

  • Explain merge sort in Java.

  • Describe the process for using Java quicksort.

  • How do you create a binary tree in Java?

Java threading interview questions

Here are some questions you might be asked about threading in Java:

  • What is threading in Java?

  • What is multithreading in Java?

  • Explain some advantages of multithreading.

  • What is the difference between a thread and a process?

  • What is the difference between a thread class and a runnable interface in Java?

  • Explain whether or not it is possible to start a thread twice.

  • What are daemon threads?

  • Explain synchronisation in Java.

  • What is a deadlock?

  • Explain thread scheduler.

  • Explain the thread pool in Java.

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