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Java for Testers Interview Questions And Answers – Part 1

Java for Testers Interview Questions And Answers – Part 1

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)

Please leave your questions/comments/feedback below.

Happy Learning ?

About Me > Bijan Patel

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On a mission to contribute to the Software Testing Community in all possible ways.

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