Java is a popular programming language that allows developers to create complex and fool-proof programs. If you are a developer attending a programming and technical interview, you will be asked Java programming interview questions at various stages of your interview, regardless of the company you are applying to. To assess your knowledge of the language, FAANG, and tier-1 companies ask core Java programming interview questions about writing code and programming theory. Given that Java is one of the most widely used programming languages globally, practicing responses to common Java interview questions is essential for advancing in competitive technical interviews.
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Let's take a look at some of the most common Java programming interview questions and answers for freshers and experienced developers that are asked in technical interviews at FAANG and tier-1 companies.
Here’s what we’ll discuss in this article:
In this section, we’ll look at the most popular Java Programming interview questions and answers.
While Java is classified as an Object-Oriented Programming Language, it isn’t 100% Object-Oriented because it uses eight primitive data types which aren’t objects. The eight primitive data types include - boolean, double, long, short, float, char, int, and byte.
Wrapper classes in Java are essentially used to convert primitive data types into objects in the OOP model. Wrapper classes wrap these primitive data types, a total of 8 in number, into objects of the particular class.
This is one of the most common Java programming interview questions asked in technical interviews. Constructors in Java are blocks of code that are used to initialize objects in a class. Constructors in Java are required to have the same name of the class to initialize objects. The two types of constructors in Java are Default Constructors and Parameterized Constructors.
In Java, super keywords have the following important functions:
Using Pointers generally increases the program’s complexity. Java is a language that maintains the simplicity of code. More so, the Java Virtual Machine implicitly allocates memory to prevent direct access of memory by the user, averting the need for pointers.
This is one of the most common Java programming interview questions asked in technical interviews. JIT, short for Just In Time, is a compiler that converts Java Bytecode into instructions for the processor. The JIT compiler in Java is activated the moment a method is invoked.
Access Modifiers/Specifiers are special keywords used to protect the information within a class. These keywords restrict access to data members, methods, and constructors in a class. The four different types of Access Specifiers in Java are:
The main OOPs concepts that the Java language exhibits are:
Reflection in Java is fundamentally a Runtime API that helps track changes in the behavior of Classes and Objects contained within the Class, methods, and interfaces. With Reflection, programmers can analyze the behavior of various elements at Runtime without requiring to know whether they’ve been called at compile time.
The Java String Pool is a collection of Strings stored in the heap memory. The String Pool checks whether a certain new object is already present when it is created. If the Object is present in the pool, the reference is accordingly returned to the variable. Else, a new object is created in the heap memory, and the appropriate reference is returned.
Take a look at some Java Interview Questions for Software Developers with five years of experience.
In this section, we’ll look at some additional Java programming interview questions that you can practice for your upcoming software developer interview.
Let’s look at some Java OOPS Concepts interview questions:
Take a look at some of the most commonly asked Core Java Interview Questions here.
In this section, we’ll look at some advanced Java programming interview questions that often appear in technical interviews.
These basic and advanced Java Programming interview questions and answers will help you gear up for your upcoming software engineering interview.
Check some Java Multithreading Interview Questions here.
Q1. What are the important Java programming concepts that feature in technical interviews?
Some important concepts around which Java programming interview questions are asked include - polymorphism, data binding, abstraction, encapsulation, methods, constructors, multithreading, functions, access specifiers, and classes.
Q2. Are Java programming interview questions asked at Systems Design interviews?
Yes, especially if you are a backend developer who codes in Java, you can expect questions around core Java programming concepts at Systems design interviews.
Q3. What is Multithreading in Java?
Multithreading is a core Java programming feature that enables multiple threads, essentially sub-processes, to run simultaneously and prevent runtime complications. Multithreading in Java helps to build complex software and programs.
Q4. Which Class is considered as the SuperClass in Java Object-Oriented Programming?
In Java, the Object Class is considered the SuperClass of all classes.
Q5. What coding concepts feature in Java technical interviews at FAANG+ companies?
At FAANG+ technical interviews, you’re asked to solve problems around core data structures and algorithms using Java. The important concepts include - arrays, strings, recursion, hash tables, linked lists, trees, graphs, and dynamic programming.
If you’re getting ready for your upcoming Java developer interview, register for our free webinar to get insightful guidance from industry experts on how to nail technical interviews at top companies.
At Interview Kickstart, we’ve trained over 9,000 engineers to land lucrative offers at the biggest tech companies. Our instructors, who are FAANG hiring managers, know what it takes to nail tough tech interviews at top technology companies.