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Java Interview questions and answers


JAVA interview questions 

Here in this Java interview blog, You will get Important and frequently asked Java Interview questions. Java is one of the best programming languages used for web and android development. Java is an Object-oriented programming Langauge used widely across the world. There are lots of job opportunities in Java. Various big technologies are using Java as their programming language for back end and web development.

Java Interview questions and answers

Here is the list of frequently asked Java Interview questions:


1. What is the difference Between JDK, JRE, and JVM?

JDK - It stands for Java Development Kit. It is the software development environment used for web and app development in the Java language. JDK allows the user to make a java program that can be executed with the help of JRE and JVM.

JRE - It stands for Java runtime environment. It is responsible for executing java programs. It allows memory during program execution and loads class files during program execution.

JVM - It stands for Java virtual machine. It is used for compiling Java programs. it converts java programs into byte codes. byte code is generated when we execute any program.


2. What is the difference between C and Java Programming Language?

C programming language: It is the general-purpose procedural programming language. It is a compiler-based programming language. The speed and low memory consumption are some of the best properties of the C programming language.


Java - It is the object-oriented programming language released by sun microsystems in 1995. It is a simple and secured programming language. There is a lack of pointers in java which causes sometimes security problems. It has many amazing features which resemble Modern-day programming languages such as Python.


3.Write a program in Java to check whether two Strings are Anagram or not?


package MyCode;
import java.util.Scanner;

public class back {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        String s ="COURPEDIA";
        String p="PEDIACUOR";
        int count=0;
        if(s.length()==p.length())
        {
        for(int i=0;i<s.length();i++)
        {
           for(int j=0;j<s.length();j++)
            {
             if(s.charAt(i)==p.charAt(j))
                {
                 count++;
                }
            }
        }
        if(count==s.length())
System.out.println("The strings are Anagram");
        else
     System.out.println("Not Anagram");
        
        }
        else
        {
 System.out.println(" strings are not anagram");
        }
        
        
        
    }

}


4.What is Classloader in Java?

The Java virtual machine subsystem is used to load class files during the execution of the java program.

Types of ClassHolder in java:

There are three types of Classholder in java

1. Bootstrap Classholder

2. Extension Classholder

3.System/Application Classholder.


5.What is the purpose of static methods and static variables in the java programming language?

we use static methods and static variables in java so that methods and variables can easily be shared between different objects of the class instead of making different copies for each object.


6.Write a program in java to print the Fibonacci sequence of n numbers?


package MyCode;
import java.util.Scanner;

public class Fibinacci {

    public static void main(String[] args) {
   // TODO Auto-generated method stub
Scanner sc= new Scanner(System.in);
System.out.println("enter number");
  int n= sc.nextInt();
        int a=0;
        int b=1;
        System.out.print(a);
        System.out.print(b);
        for (int i=0;i<=n-2;i++)
        {
       int c= a+b;
        System.out.print(c);
         a=b;
        b=c;
        }
    }

}


7.Write a program in Java to print the sum of digits of a number.


package MyCode;

import java.util.Scanner;

public class Pattern3 {

public static void main(String[] args){
        
        
// TODO Auto-generated method stub
Scanner sc= new Scanner(System.in);
System.out.println("enter number");
       int n=sc.nextInt();
        int temp=n;
        
        int sum=0;
        while ( temp>0){
            int lastdig=temp%10;
            temp=temp/10;
            
            
            sum=sum+lastdig;
            
            
        }
        System.out.println(sum);
    
    }
    }


8.Write a program to print the star pattern given below in java?

*****************

****************

***************

**************

*************

************

***********

**********

*********

********

*******

******

*****

****

***

**


package MyCode;
import java.util.Scanner;

public class NewTopic {

public static void main(String[]args) 
{
Scanner sc = new Scanner(System.in);
System.out.println("enter number");
    int n=sc.nextInt();
    
    for(int i=0;i<n;i++) {
      for(int j=n;j>=i;j--) {
       System.out.print("*");
                
            }
       System.out.println();
            
        }
     

    }

}


9.What are various access specifiers in Java?

Access specifiers are keywords in java used to fix the scope of any method, class, variable.

There are four access specifiers in java

1.Public

2.Protected

3.Default

4.Private


Also, read- [C Programming interview questions]


10. Why does Java does not make use of Pointers?

As java is a well-furnished language, it does not use a pointer because the pointer leads to data insecurity and generates some garbage values during program execution. It makes the program slow and erroneous. That's why Java does not make use of pointers.


            There are lots of Java questions that you will get here from time to time. We will regularly update the best questions and new concepts on the java programming language. so be updated with us.