Top 20 Elementary Java Programming Questions for Interview

If you are looking for a job in the field of java programming and have prepared a lot for the interview but still stressed about the interview questions. We are here to help you regarding your problem; we will provide you the frequently asked java programming questions for interview along with answers.

We are familiar with the truth that coding is an essential part of all programming jobs. It is not advisable to hire anyone without testing their coding knowledge. All the huge tech companies such as Google, Facebook, and Amazon test the coding skills of the interviewee, especially Amazon initially provide online coding exercises to choose the java programmer. This online recruitment procedure tells you the requirements, and you need to write a program within a limited time assigned by them.This type of test is difficult to crack if you don’t know how to code.

In today’s world Java is used in almost every technical field so, Java certification is in demand in the programming domain. Java is a fast, secure and reliable programming language, so if you want to stand you have to prepare the different questions related to this field.

In this blog, we are going to list the java programming questions for interview that will help you to strengthen your preparation.

Mostly Asked Java Programming Questions for Interview-

Read these questions and answers and sharpen your skill to give your best in today’s cut-throat competition.

1.What do you mean by Java?

Java is a powerful, object-oriented, secure, high-level language. Its other features are, it provides high performance, platform-independent, portable, and multithreaded language. It offers its own JRE and API, so it is also called a platform. Java language was developed in 1991 by Jame Gosling.

2.Is Java 100% object-oriented?

No, it is not 100% object-oriented. This is because it uses eight primitive data types that are not objects, namely int, char, float, byte, double, long, short, boolean.

3.What are JDK, JRE, JVM, and how are they different?

JDK- JDK (Java Development Kit) is an essential tool to compile, document, and package Java programs. It involves JRE and tools for development.

JRE- JRE ( Java Runtime Environment) is associated with a runtime environment to execute Java bytecode. It is the physical existing implementation of JVM.

JVM- JVM (Java Virtual Machine) is an abstract machine. It works on three notations, specification, implementation, and runtime instance. Apart from this, it also offers a runtime environment to execute the Java bytecode.

4.Why is Java not dependent on any platform?

Java is platform-independent as we can use any system to run its byte codes regardless of any fundamental operating system. It provides its own JRE and API to run the program.

5.How to sort a primitive array in Java?

It is easy to sort a primitive array in a natural order. We can sort an array by using the sort method.

int[] array = {2,5,4,-2,-5,}

Array.sort (array);

System.out.println(arrays.tostring(array));

Output will be

-2,-5,2,4,5

6.What is the basic difference between C++ and Java?

C++ is an extension of the C language, and it is platform-dependent. System programming is the main objective of this language. On the other hand, Java is platform-independent. It is specially developed for application programming such as Windows, web-based, enterprise, and mobile applications.

7.What is Platform?

It is a software or hardware environment that executes a piece of software. Two types of platforms are there, software and hardware-based. Java offers a software-based platform.

8.How are Java platforms and other platforms distinct?

Java platform is software-oriented, and programs are executed using this software or platform. However, other platforms can be hardware or software-oriented. Other platforms have the hardware components only.

9.What is the reason behind the “write once and run anywhere” nature of Java?

It’s bytecode that is not platform-specific, and we can run it on any computer system. An intermediate language (java compiler) convert the programs into a class file(byte code)

10.What are constructors in Java and their types?

It represents a block of code used to initialize an object. A constructor and class should have similar names. It is automatically introduced when we create an object and has no return type.

Two types of constructors are here-

  1. Default Constructor- This constructor does not take any input. As the name suggests, these are created by default if the user does not define the constructor. It is used to create an object and aims to initialize the instance variables with the default values.
  1. Parameterized Constructor- It is efficient to initialize the instance variables along with the provided values. In simple words, the constructor that can take arguments is known as parameterized constructors.

11.What do you understand about the ‘super’ keyword in Java?

It is a referred variable to refer to parent class objects. This keyword came with the concept of inheritance. An instance of parent class is created when you create the instance of a subclass.

Various functions of Super keyword-

  • It is used to refer immediate parent instance variable
  • We use it when we need to call the immediate parent constructor
  • Super is usable in calling the parent class method.

12.What is a static variable?

The static keyword is associated with the class rather than the instance of the class. It is mainly used for memory management. We can apply this keyword with methods, blocks, nested, and variable class.

The static may be-

variable (can be called class variable)

method, (can be called a class method)

block

nested class

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13.Why are Pointers not used in Java?

Java avoids pointers because they are not safe to use and increases the complications in the program. Java is a simple to use language; it does not require the use of pointers. In addition, for Java, JVM is there for implicit memory allocation, so to avoid direct access to memory by the user, pointers are refused in Java.

14.What Is Object-Oriented Programming?

Object-oriented programming is known as OOPs. It is an approach to organize the programs around objects instead of logic and functions. It aims at object manipulation rather than logic. 

OOPs is considered as the best model for the large and complex codes for updations and maintenance.

15.If I don’t put any statement on the command line, what will the String array’s value be passed into the main() method, empty or NULL?

It can’t be null. It should be empty.

16.What will happen if i write Static public void in place of public static void?

The order of the specifiers does not matter in java programming; the program will compile and run properly.

17.What is the output of the program written below?

class Test

{

public static void main (string args[])

{

System.out.println(19+50+”javadisplay”);

System.out.println(“Javadisplay”+19+50);

}}

The output will be-

69Javadisplay for the first statement, in this case, their sum 69 is taken as numbers  and concatenated with the string javadisplay, so the output is 69Javadisplay.
Javadisplay1950 for the second statement, because 19 and 50 are taken as string, and their concatenation with Javadisplay is Javadisplay1950.

18.What are the different Access specifiers in Java?

Access specifiers are the keywords to define the access scope of the class, Method, or variable. There are four types of access specifiers in Java.

Public: Any class and Method can access these. Variable methods and classes are known as public in Java.

Default: All the classes, methods, and variables are of default scope by default. These are used in the package only.

Protected– Can be accessed by the class and subclass of the same package.

Private– Can be accessed within the class only as class methods or variables are defined as private.

19.What do you mean by Map in Java?

A map is an interface of a package that maps the unique keys to the values. It is slightly different from the other collection types because a map interface is not a subset of the main collection interface. In a Map-

  • Each key can map a maximum of one value.
  • Duplicate keys not present.

20.How to create an object in Java?

An object is an actual world entity that possesses a state, identity, and behavior. We use the ‘new’ keyword to create an object.

Finally these are some basic java programming questions for interview. However these questions are not the sure short questions but can help you to boost your preparation. There are thousands of questions an interviewer can think and ask on the basis of Java programming so it is difficult to estimate the fixed questions for the interview.

Conclusion 

In this article, we have discussed the most important java programming questions for interview. I hope it will help you to strengthen your knowledge and skills. You can read this question before your interview as a plus point. After reading these questions you will be confident and motivated in the interview and can crack it with a caliber. The interviewer can test your programming knowledge in the written form so you should know how to code. Moreover, we also provide Java programming assignment help, you can discuss your requirements with our Java programming help experts anytime if you need any.