Java for Testers – Interview Questions and Answers Part-1
1) Write a simple Java program?
public class Simple{
public static void main(String[] args){
System.out.println(“Hello World”);
}
}
2) Write a Java program to print an integer value?
public class PrintInteger{
public static void main(String[] args){
int i = 1; System.out.println(i);
}
}
3) Write a Java program to print the command line arguments?
public class Sample {
public static void main(String[] args){
if (args.length > 0) {
System.out.println("The command line"+ " arguments are:");
for(String val:args)
System.out.println(val);
} else
System.out.println("No command line "+ "arguments found.");
}
}
Command Line:
Bijans-MacBook-Pro:java bijan$ javac Sample.java Bijans-MacBook-Pro:java bijan$ java Sample Java Interview Questions
The command line arguments are: Java Interview Questions
4) Write a Java program to print the input from scanner?
public class PrintScannerInput {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String name = sc.nextLine();
System.out.println("Name: "+name);
}
}
5) Write a Java program to convert from Fahrenheit to Celsius?
public class ConvertToCelsius {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Input temperature in Fahrenheit: ");
double fahrenheit = sc.nextDouble();
double celsius = ((5 * (fahrenheit - 32.0)) / 9.0);
System.out.println(fahrenheit + " degree fahrenheit is equal to " + celsius + "in celsius");
}
}
6) Write a Java program to swap two numbers?
public class SwapNumbers {
public static void main(String[] args) {
int x, y, z;
Scanner sc = new Scanner(System.in);
x = sc.nextInt(); y = sc.nextInt();
System.out.println("Before swapping\n x = " + x + "\n y = " + y);
z = x; x = y; y = z;
System.out.println("After swapping\n x = " + x + "\n y = " + y);
}
}
7) Write a Java program to swap two numbers without using third variable?
public class SwapNumberWithoutVariable {
public static void main(String[] args) {
int x = 10;
int y = 5;
x = x + y;
y = x - y;
x = x - y;
System.out.println("After swapping: " + " x is " + x + " and " + "y is "+ y);
}
}
8) Write a Java program to add two numbers?
public class AddNumbers {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int a = sc.nextInt(); int b = sc.nextInt();
int sum = a + b;
System.out.println("Sum of two numbers is: " + sum);
}
}
9) Write a Java program to find the largest number?
public class FindLargestNumberInArray {
static int array[] = {21,98,13,9,34};
public static void main(String[] args){
int maxNumber = findLargestNumber();
System.out.println("Maximum number in the array: "+ maxNumber);
}
private static int findLargestNumber(){
int max = array[0];
for(int i =0;i<array.length;i++){
if(array[i]>max)
max = array[i];
}
return max;
}
}
10) Write a Java program to demonstrate if..else statement ?
public class FindNumberIsPrime {
public static void main(String[] args){
boolean flag = false;
System.out.println("Enter input number");
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
for(int i=2;i<=num/2;i++){
if(num%i==0){
flag = true;
break;
}
}
if(!flag){
System.out.println(num + " is a prime number");
} else{
System.out.println(num + " is not a prime number");
}
}
}
11) Write a Java program to demonstrate nested if … else if .. statement?
public class IfElseDemo {
public static void main(String[] args){
int i =20;
if(i == 10)
System.out.println("i is 10");
else if(i == 15)
System.out.println("i is 15");
else if(i == 20)
System.out.println("i is 20");
else
System.out.println("i is not present");
}
}
12) Write a Java program to demonstrate nested if …else statement?
class Ladder {
public static void main(String[] args) {
int number = 0;
if (number > 0) {
System.out.println("Number is positive.");
} else if (number < 0) {
System.out.println("Number is negative.");
} else {
System.out.println("Number is 0.");
}
}
}
13) Write a Java program to find odd and even numbers ?
public class FindOddEvenNumbers {
public static void main(String[] args){
Scanner sc= new Scanner(System.in);
System.out.println("Enter a number: ");
int inputNumber = sc.nextInt();
findNumber(inputNumber);
}
public static void findNumber(int number){
if(number%2!=0){
System.out.println("Number is odd");
}
else {
System.out.println("Number is even");
}
}
}
14) Write a Java program to compare two strings?
public class CompareTwoStrings {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("Enter first string");
String first = sc.next();
System.out.println("Enter second string");
String second = sc.next();
compare(first,second);
}
public static void compare(String s1, String s2){
if(s1.compareTo(s2)==0) {
System.out.println("Strings are equal");
} else {
System.out.println("Strings are not equal");
}
}
}
15) Write a Java program to demonstrate for loop ?
public class ReverseSentenceWordByWord {
public static void main(String[] args){
String sentence = "Java Interview Questions";
String reversedSentence = reverseSentence(sentence);
System.out.println(reversedSentence);
}
public static String reverseSentence(String sentence){
String reverse = "";
String[] words = sentence.split("\\s");
for(int i=words.length-1;i>=0;i--){
reverse = reverse + words[i] + " ";
}
return reverse;
}
}
16) Write a Java program to print stars using for loop, where the number of stars printed should be equal to the row number?
public class PrintStarPatternInRow {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of rows");
int rows = sc.nextInt();
printStars(rows);
}
public static void printStars(int n){
for(int i=0;i<n;i++){
for(int j=0;j<=i;j++){
System.out.print("* ");
}
System.out.println();
}
}
}
17) Write a Java program to demonstrate while loop?
class WhileLoopExample {
public static void main(String args[]){
int i=10;
while(i>1){
System.out.println(i);
i--;
}
}
}
18) Write a Java program to print the entered number in reverse?
public class ReverseNumber {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number");
int num = sc.nextInt();
reverseNumber(num);
}
public static void reverseNumber(int number){
int reverse = 0;
while(number!=0){
int digit = number % 10;
reverse = reverse * 10 + digit;
number = number/10;
}
System.out.println("Reversed number " + reverse);
}
}
19) Write a Java program to demonstrate the usage of break statement inside while loop?
class BreakExample {
public static void main(String[] args) {
Double number, sum = 0.0;
Scanner input = new Scanner(System.in);
while (true) {
System.out.print("Enter a number: ");
number = input.nextDouble();
if (number < 0.0) {
break;
}
sum += number;
}
System.out.println("Sum = " + sum);
}
}
20) Write a Java program to demonstrate the usage of break and continue statements inside while loop?
public class ContinueExample {
public static void main(String args[]) {
int [] numbers = {10, 20, 30, 40, 5};
for(int x : numbers ) {
if( x == 30 ) {
continue;
}
System.out.print( x );
System.out.print("\n");
}
}
}
21) Write a Java program to print the alphabets using for loop?
public class PrintAlphabets
{
public static void main(String[] args)
{
char i;
System.out.printf("The Alphabets from A to Z are: \n");
for (i = 'A'; i <= 'Z'; i++)
{
System.out.printf("%c ", i);
}
}
}
22) Write a Java program to demonstrate for each loop?
public class FindHighestMarks {
public static void main(String[] arg) {
int[] marks = { 125, 132, 95, 116, 110 };
int highest_marks = maximum(marks);
System.out.println("The highest score is " + highest_marks);
}
public static int maximum(int[] numbers) {
int max = numbers[0];
// for each loop
for (int num : numbers) {
if (num > max) {
max = num;
}
}
return max;
}
}
23) Write a Java program for printing the Multiplication table?
public class MultiplicationTable {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("Enter number");
int number = sc.nextInt();
System.out.println("Enter multiplication range");
int range = sc.nextInt();
for(int i=1;i<=range;i++){
System.out.printf("%d * %d = %d \n", number, i, number * i);
}
}
}
24) Write a Java program for printing the prime numbers?
public class FindNumberIsPrime {
public static void main(String[] args){
boolean flag = false;
System.out.println("Enter input number");
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
for(int i=2;i<=num/2;i++){
if(num%i==0){
flag = true;
break;
}
}
if(!flag){
System.out.println(num + " is a prime number");
} else{
System.out.println(num + " is not a prime number");
}
}
}
25) Write a Java program to check whether a given number is Armstrong ?
public class ArmstrongNumber {
public static void main(String[] args){
int c=0,a,temp;
Scanner sc = new Scanner(System.in);
System.out.println("Enter a number");
int num = sc.nextInt();
temp = num;
while(num>0){
a=num%10;
num=num/10;
c=c+(a*a*a);
}
if(temp==c) {
System.out.println(temp + " is an Armstrong number");
} else
System.out.println(temp + " is not an armstrong number");
}
}
Next Steps:
> More interview questions and answers on Selenium Java, continue to the next post (Click on Next Post link below)
> Check complete Selenium Java interview questions and answers here (Click here)
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