Introduction to Java & BlueJ

Question 1

Define objects. Give a real life example to explain objects along with their attributes and behaviour.

Question 2

What is class?

Question 3

What do you understand by the term Polymorphism?

Question 4

What are operators? Why do we need them?

Question 5

What do you understand by the term Keyword?

Question 6

What are variables? How are they different from Constants?

Question 1

Ritika has written a program in Java. After the successful compilation of her program, which option should she select to run it?

Question 2

Kareena is writing a program in Java to calculate the average of three subjects. Which operators will she use for the same?

Question 1

The Java programming language is an Object Oriented Programming language.

Question 2

Encapsulation is the technique of binding both data and functions together.

Question 3

A Class is a blueprint that defines data and functions common to all objects of a certain kind.

Question 4

The smallest meaningful element of a Java program is called a Token.

Question 5

Initialization is a process of assigning some initial value to a variable.

Question 1

Write a program to print, "Welcome to the World of Computers".

public class KboatWelcome
{
    public static void main(String args[]) {
        System.out.println("Welcome to the World of Computers");
    }
}

Output

Question 2

Write a program to print your Name, Class, Roll_No, Marks and Age. Name this file, `MyProfile'.

public class MyProfile
{
    public static void main(String args[]) {
        System.out.println("Name: Sneha Nayak");
        System.out.println("Class: 8C");
        System.out.println("Roll No: 24");
        System.out.println("Marks: 87");
        System.out.println("Age: 15");
    }
}

Output

Question 3

Write a program to print your School name four times in separate lines.

public class KboatSchoolName
{
    public static void main(String args[]) {
        System.out.println("St. Francis' College");
        System.out.println("St. Francis' College");
        System.out.println("St. Francis' College");
        System.out.println("St. Francis' College");
    }
}

Output

Question 4

Write a program to find the sum and average of three numbers.

public class KboatSumAvg
{
    public static void computeSumAvg(int a, int b, int c) {
        System.out.println("The three numbers are " 
          + a + ", " + b + ", " + c );
        int sum = a + b + c;
        double avg = sum / 3.0;
        System.out.println("Sum = " + sum);
        System.out.println("Average = " + avg);
    }
}

Output

Question 5

Write a program to interchange the value of two numbers without using the third variable.

public class KboatSwap
{
    public static void swapNumbers(int a, int b) {
        System.out.println("The numbers are:");
        System.out.println("a=" + a + " b=" + b);
        a = a + b;
        b = a - b;
        a = a - b;
        System.out.println("The numbers after interchange:");
        System.out.println("a=" + a + " b=" + b);
    }
}

Output

Question 6

Write a program to calculate the compound interest.

public class KboatInterest
{
    public static void computeInterest(double p, double r, int t) {
        double amt = p * Math.pow(1 + (r / 100 ), t);
        double interest = amt - p;
        System.out.println("Compound Interest = " + interest);
    }
}

Output

Question 7

Write a program to calculate the tax for a taxable income of Rs. 4,10,000, if the tax rate is fixed at 3.2%.

public class KboatTax
{
    public static void main(String args[]) {
        int income = 410000;
        double rate = 3.2;
        double tax = income * rate / 100;
        System.out.println("Tax = " + tax);
    }
}

Output

Question 8

Create a program that will generate a bill at McDonald's for four vegetable burgers (@ Rs 45 per vegetable Burger) and three vegetable McPuffs (@ Rs 25 per vegetable McPuff). There is a special Independence Day discount of Rs 50 on the final bill amount.

public class KboatMcDBill
{
    public static void main(String args[]) {
        int vegBurgerCost = 4 * 45;
        int vegMcPuffCost = 3 * 25;
        int total = vegBurgerCost + vegMcPuffCost;
        int amt = total - 50;
        System.out.println("4 Vegetable Burgers @ 45 = " + vegBurgerCost);
        System.out.println("3 Vegetable McPuffs @ 25 = " + vegMcPuffCost);
        System.out.println("Total = " + total);
        System.out.println("Discount = 50");
        System.out.println("Final Bill = " + amt);
    }
}

Output

Question 1

A .......... is a named location in the memory, which stores data temporarily.

1. Identifier
2. Keyword
3. Variable ✓

Question 2

What does OOP mean?

1. Object Oriented Programming ✓
2. Object Oriented Procedure
3. Object Origin Program

Question 3

Which among the following feature is used to manage the complexity of the system?

1. Abstraction ✓
2. Polymorphism
3. Encapsulation

Question 4

A Java program is compiled into an intermediate language called ..........

1. Source Code
2. Bytecode ✓
3. None of these

Question 5

The .......... works on a single variable or constant.

1. Unary Operator ✓
2. Arithmetic Operator
3. Relational Operator

Question 6

Which symbol is used to combine two or more items in a single line?

1. ?
2. + ✓
3. !

Question 1

Polymorphism allows a function to behave differently for different objects.
True

Question 2

Constants mean the fixed values that do not change during the execution of a program.
True

Question 3

The main() function indicates that the execution of the Java program will begin from this point.
True

Question 4

Every Java statement must end with a colon.
False

Question 5

Inheritance is a feature using which an object in one class acquires the properties of another class.
True

Question 6

While comparing two variables, their data types should not be the same.
False