Java Programming practicals — MSBTE

Every practical of MSBTE K-scheme Java Programming (314317) with 3 different tested programs, real output, explanation and viva questions.

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Practical 1Compulsory

Set up the Java development environment (command prompt and IDE)

Aim: Install the JDK, set PATH and CLASSPATH, compile and run a program from the command prompt and from an IDE.

QSet up the Java development environment and run your first Java program.

Showing answer A of 3 · tap A, B or C to see the others

Download the JDK (Oracle JDK or OpenJDK, version 17 or later) and install it, e.g. in C:\Program Files\Java\jdk-21.
Open Start → "Edit the system environment variables" → Environment Variables.
PATH: edit Path → New → C:\Program Files\Java\jdk-21\bin (this lets you type javac and java anywhere).
CLASSPATH (optional): New variable CLASSPATH = .; (the dot means "current folder").
Open a new Command Prompt and check: javac -version and java -version.
Save the program as Main.java, then run: javac Main.java and java Main

Output

Hello! Java is installed correctly.
Java version : 21
Running from the command prompt.

public class Main
{
    public static void main(String[] args)
    {
        System.out.println("Hello! Java is installed correctly.");
        System.out.println("Java version : " + System.getProperty("java.specification.version"));
        System.out.println("Running from the command prompt.");
    }
}

Install the JDK first (Eclipse needs it).
Download "Eclipse IDE for Java Developers" from eclipse.org and start it; choose a workspace folder.
File → New → Java Project → name it JPR → Finish.
Right-click src → New → Class → name Main, tick "public static void main" → Finish.
Type the program and press Ctrl + F11 (Run). Output appears in the Console tab.

Output

Practical 1 done in Eclipse
Project > Package > Class created successfully.

public class Main
{
    public static void main(String[] args)
    {
        String ide = "Eclipse";
        int practical = 1;
        System.out.println("Practical " + practical + " done in " + ide);
        System.out.println("Project > Package > Class created successfully.");

Install the JDK and VS Code.
In VS Code open Extensions (Ctrl + Shift + X) and install "Extension Pack for Java" (Microsoft).
Open a folder, create Main.java and type the program.
Click "Run" above main() or press F5. The program asks for input in the Terminal.

Output

Enter your name: Riya
Welcome Riya, your Java setup in VS Code works!

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter your name: ");

🎤 Viva questions (5)

Q. What is the difference between JDK, JRE and JVM?: A. JVM runs bytecode; JRE = JVM + libraries to run programs; JDK = JRE + tools like javac to develop programs.
Q. What does javac do?: A. It compiles .java source code into .class bytecode.
Q. Why is Java platform independent?: A. Bytecode runs on any machine that has a JVM — "write once, run anywhere".
Q. What is the PATH variable used for?: A. It tells Windows where javac and java are, so they run from any folder.
Q. Why is main() static?: A. The JVM calls main() before any object exists, so it must belong to the class.

Practical 2

Evaluate different types of expressions

Aim: Use arithmetic, relational, logical, bitwise, increment/decrement and conditional operators in expressions.

QWrite a program to evaluate different types of expressions.

Showing answer A of 3 · tap A, B or C to see the others

Output

a + b = 22
a - b = 12
a * b = 85
a / b = 3   (integer division)
a % b = 2   (remainder)
(double) a / b = 3.4
x += 5  -> 15
x *= 2  -> 30
x -= 4  -> 26

public class Main
{
    public static void main(String[] args)
    {
        int a = 17, b = 5;
        System.out.println("a + b = " + (a + b));
        System.out.println("a - b = " + (a - b));
        System.out.println("a * b = " + (a * b));

Output

Enter your age and percentage: 19 72.5
age >= 18          : true
per > 60           : true
age == 18          : false
age >= 18 && per > 60 : true
age < 18 || per > 90  : false
!(per > 60)        : false

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter your age and percentage: ");

Output

a & b  = 8
a | b  = 14
a ^ b  = 6
~a     = -13
a << 2 = 48
a >> 2 = 3
pre = 6, post = 6, i = 7
Conditional: a is bigger

public class Main
{
    public static void main(String[] args)
    {
        int a = 12, b = 10;             // 12 = 1100, 10 = 1010
        System.out.println("a & b  = " + (a & b));
        System.out.println("a | b  = " + (a | b));
        System.out.println("a ^ b  = " + (a ^ b));

🎤 Viva questions (5)

Q. What is an expression?: A. A combination of variables, constants and operators that gives a value.
Q. What is the difference between / and %?: A. / gives the quotient, % gives the remainder.
Q. What is the difference between ++i and i++?: A. ++i increments before use, i++ uses the old value and then increments.
Q. What is the difference between & and &&?: A. & is bitwise (and evaluates both sides); && is logical AND with short-circuit.
Q. What is type casting?: A. Converting one data type into another, e.g. (double) a.

Practical 3

if statements, switch-case and loops (for, while, do..while)

Aim: Write programs using all forms of if, the switch statement and the three loops.

Q1Program 1: use all forms of the if statement.

Showing answer A of 3 · tap A, B or C to see the others

Output

Enter percentage: 68.4
Grade: First class

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter percentage: ");

Output

Enter three numbers: 45 92 67
Largest = 92

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter three numbers: ");

Output

Enter a number: 37
37 is positive
37 is odd

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");

Q2Program 2: use the switch-case statement.

Showing answer A of 3 · tap A, B or C to see the others

Output

Enter two numbers: 24 6
Choose operator (+ - * /): /
Result = 4.0

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter two numbers: ");

Output

Enter day number (1-7): 5
Day: Friday

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter day number (1-7): ");

Output

Enter a letter: E
e is a vowel

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a letter: ");

Q3Program 3: use the for, while and do..while loops.

Showing answer A of 3 · tap A, B or C to see the others

Output

Enter a number: 7
7 x 1 = 7
7 x 2 = 14
7 x 3 = 21
7 x 4 = 28
7 x 5 = 35
7 x 6 = 42
7 x 7 = 49
7 x 8 = 56
7 x 9 = 63
7 x 10 = 70

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");

Output

Enter a number: 4721
Sum of digits = 14
Reverse       = 1274

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");

Output

1. Square  2. Cube  3. Exit
Your choice: 1
Enter number: 6
Square = 36
1. Square  2. Cube  3. Exit
Your choice: 2
Enter number: 3
Cube = 27
1. Square  2. Cube  3. Exit
Your choice: 3
Bye!

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int choice;

🎤 Viva questions (5)

Q. What is the difference between while and do..while?: A. while checks the condition first; do..while runs the body once before checking.
Q. What happens if break is missing in a switch case?: A. Execution falls through into the next case.
Q. Can switch work with String in Java?: A. Yes, from Java 7 onwards.
Q. What is a nested if?: A. An if statement written inside another if or else block.
Q. What is an infinite loop?: A. A loop whose condition never becomes false, e.g. for(;;).

Practical 4Compulsory

Methods of the String class and the StringBuffer class

Aim: Use common methods of String (immutable) and StringBuffer (mutable).

Q1Program 1: demonstrate methods of the String class.

Showing answer A of 3 · tap A, B or C to see the others

Output

String       : Java Programming
length()     : 16
charAt(5)    : P
toUpperCase(): JAVA PROGRAMMING
toLowerCase(): java programming
substring(5) : Programming
indexOf('a') : 1
replace      : Core Java Programming
contains Pro : true
trim()       : [hello]

public class Main
{
    public static void main(String[] args)
    {
        String s = "Java Programming";
        System.out.println("String       : " + s);
        System.out.println("length()     : " + s.length());
        System.out.println("charAt(5)    : " + s.charAt(5));

Output

Enter first word : India
Enter second word: INDIA
equals            : false
equalsIgnoreCase  : true
compareTo         : 32
startsWith("In") : true
concat            : India INDIA

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter first word : ");

Output

Enter a sentence: Madam teaches Java
Words      : 3
First word : madam, reversed: madam
It is a palindrome

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a sentence: ");

Q2Program 2: demonstrate methods of the StringBuffer class.

Showing answer A of 3 · tap A, B or C to see the others

Output

Start       : Java
append()    : Java Programming
insert()    : Core Java Programming
replace()   : Advanced Java Programming
delete()    : Java Programming
reverse()   : gnimmargorP avaJ
length()    : 16
capacity()  : 42

public class Main
{
    public static void main(String[] args)
    {
        StringBuffer sb = new StringBuffer("Java");
        System.out.println("Start       : " + sb);
        sb.append(" Programming");
        System.out.println("append()    : " + sb);

Output

Enter a word: Racecar
Reverse: racecaR
Racecar is a palindrome

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a word: ");

Output

setCharAt     : Hello World
deleteCharAt  : HelloWorld
charAt(4)     : o
indexOf("W")  : 5
setLength(5)  : Hello

public class Main
{
    public static void main(String[] args)
    {
        StringBuffer sb = new StringBuffer("hello world");
        sb.setCharAt(0, 'H');
        sb.setCharAt(6, 'W');
        System.out.println("setCharAt     : " + sb);

🎤 Viva questions (5)

Q. Why is String immutable?: A. Once created, its value cannot change; methods return new String objects. This makes it safe to share.
Q. What is the difference between String and StringBuffer?: A. String is immutable; StringBuffer is mutable and changes the same object.
Q. What is the difference between StringBuffer and StringBuilder?: A. StringBuffer is synchronized (thread-safe); StringBuilder is not, so it is faster.
Q. What is the default capacity of StringBuffer?: A. 16 characters (plus the length of the initial string).
Q. What is the difference between == and equals()?: A. == compares references; equals() compares contents.

Practical 5Compulsory

Use of arrays and Vectors

Aim: Store data in one- and two-dimensional arrays, and in a growable Vector.

Q1Program 1: demonstrate the use of arrays.

Showing answer A of 3 · tap A, B or C to see the others

Output

How many numbers? 5
Enter 5 numbers: 12 45 7 30 18
Sum     = 112
Average = 22.4
Largest = 45

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("How many numbers? ");

Output

Original : [67, 45, 89, 23, 78]
Bubble   : [23, 45, 67, 78, 89]
Names    : [Anita, Kiran, Ravi, Zoya]

import java.util.Arrays;

public class Main
{
    public static void main(String[] args)
    {
        int[] marks = {67, 45, 89, 23, 78};
        System.out.println("Original : " + Arrays.toString(marks));

Output

Sum of matrices:
10  10  10  
10  10  10  
10  10  10

public class Main
{
    public static void main(String[] args)
    {
        int[][] a = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
        int[][] b = {{9, 8, 7}, {6, 5, 4}, {3, 2, 1}};
        int[][] c = new int[3][3];

Q2Program 2: demonstrate the use of Vectors.

Showing answer A of 3 · tap A, B or C to see the others

Output

Vector          : [C, C++, Java, Python]
insertElementAt : [C, HTML, C++, Java, Python]
remove("C++")   : [C, HTML, Java, Python]
elementAt(2)    : Java
contains Java   : true
indexOf Python  : 3
size / capacity : 4 / 10

import java.util.Vector;

public class Main
{
    public static void main(String[] args)
    {
        Vector<String> v = new Vector<>();
        v.add("C");

Output

Enter marks (-1 to stop): 72 88 64 91 -1
Marks   : [72, 88, 64, 91]
Count   : 4
Average : 78.75
First / last : 72 / 91

import java.util.Scanner;
import java.util.Vector;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);

Output

Capacity after 3 items : 3
Capacity after 4 items : 5
101  (Integer)
Neha  (String)
87.5  (Double)
A  (Character)
After removeAllElements, size = 0

import java.util.Enumeration;
import java.util.Vector;

public class Main
{
    public static void main(String[] args)
    {
        Vector<Object> v = new Vector<>(3, 2);   // capacity 3, grows by 2

🎤 Viva questions (5)

Q. What is the difference between an array and a Vector?: A. An array has a fixed size and can hold primitives; a Vector grows automatically and holds objects only.
Q. What is the default capacity of a Vector?: A. 10; it doubles when full (unless an increment is given).
Q. Is Vector synchronized?: A. Yes, its methods are synchronized (thread-safe).
Q. What is the index of the first element of an array?: A. 0
Q. What happens if you access an index outside the array?: A. ArrayIndexOutOfBoundsException is thrown.

Practical 6

Wrapper classes: primitive to object and object to primitive

Aim: Convert primitive values to wrapper objects and back, manually and with auto-boxing.

QWrite a program to convert primitive data types into objects and objects into primitive data types.

Showing answer A of 3 · tap A, B or C to see the others

Output

Objects    : 25, 9.75, J
Primitives : 25, 9.75, J
io + 5     = 30

public class Main
{
    public static void main(String[] args)
    {
        int i = 25;
        double d = 9.75;
        char c = 'J';

Output

Enter quantity and price (as text): 4 149.50
Total = 598.0
Total as String has 5 characters
Quantity in binary = 100

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter quantity and price (as text): ");

Output

Integer.MAX_VALUE = 2147483647
Integer.MIN_VALUE = -2147483648
Byte range        = -128 to 127
isDigit('7')      = true
isLetter('#')     = false
toUpperCase('q')  = Q
compare(5, 9)     = -1
a.equals(b)       = true
parseBoolean      = true

public class Main
{
    public static void main(String[] args)
    {
        System.out.println("Integer.MAX_VALUE = " + Integer.MAX_VALUE);
        System.out.println("Integer.MIN_VALUE = " + Integer.MIN_VALUE);
        System.out.println("Byte range        = " + Byte.MIN_VALUE + " to " + Byte.MAX_VALUE);
        System.out.println("isDigit('7')      = " + Character.isDigit('7'));

🎤 Viva questions (5)

Q. What is a wrapper class?: A. A class that wraps a primitive value in an object, e.g. Integer for int.
Q. What is auto-boxing?: A. Automatic conversion of a primitive into its wrapper object.
Q. What is unboxing?: A. Getting the primitive value back from the wrapper object.
Q. Why are wrapper classes needed?: A. Collections like Vector store only objects, and wrappers give useful methods like parseInt.
Q. Name the wrapper class of char and int.: A. Character and Integer.

Practical 7

Different types of constructors

Aim: Use default, parameterized and copy constructors and constructor overloading.

QWrite a program to demonstrate different types of constructors.

Showing answer A of 3 · tap A, B or C to see the others

Output

Roll: 0  Name: Not set
Roll: 12  Name: Aditi
Roll: 12  Name: Aditi

class Student
{
    int roll;
    String name;

    Student()                          // default constructor
    {
        roll = 0;

Output

Volume b1 = 1.0
Volume b2 = 27.0
Volume b3 = 40.0

class Box
{
    double l, b, h;

    Box()                      { this(1); }              // cube of side 1
    Box(double side)           { this(side, side, side); }
    Box(double l, double b, double h)
    {

Output

Name and opening amount: Sameer 200
Minimum opening balance is 500. Setting 500.
Sameer has balance Rs. 500.0

import java.util.Scanner;

class Account
{
    String holder;
    double balance;

    Account(String holder, double opening)

🎤 Viva questions (5)

Q. What is a constructor?: A. A special method with the class name and no return type that initializes a new object.
Q. What is a default constructor?: A. A constructor without parameters; Java gives one automatically if you write none.
Q. What is constructor overloading?: A. Having several constructors in a class with different parameter lists.
Q. Does Java have a built-in copy constructor?: A. No, you write it yourself by taking an object of the same class as a parameter.
Q. What is the use of this()?: A. To call another constructor of the same class; it must be the first statement.

Practical 8

Single inheritance and multilevel inheritance

Aim: Reuse a class with extends, use super, and build a multilevel chain.

Q1Program 1: implement single inheritance.

Showing answer A of 3 · tap A, B or C to see the others

Output

Name: Kavita  Salary: 45000.0
Bonus: 8000.0  Total: 53000.0

class Employee
{
    String name;
    double salary;
    Employee(String name, double salary)
    {
        this.name = name;
        this.salary = salary;

Output

I am a shape with area 0.0
I am a shape with area 28.274333882308138
Circle area (2 decimals) = 28.27

class Shape
{
    double area() { return 0; }
    void describe() { System.out.println("I am a shape with area " + area()); }
}

class Circle extends Shape
{

Output

Roll and name: 7 Pooja
Marks in 3 subjects: 78 85 69
Roll 7: Pooja
Total = 232  Percentage = 77.33333333333333

import java.util.Scanner;

class Student
{
    int roll;
    String name;
    void read(Scanner sc)
    {

Q2Program 2: implement multilevel inheritance.

Showing answer A of 3 · tap A, B or C to see the others

Output

Person created
Employee created
Manager created
501 | Rohit | Sales

class Person
{
    String name;
    Person(String name) { this.name = name; System.out.println("Person created"); }
}

class Employee extends Person
{

Output

Tata car starts with a key
Electric motor on, battery 85%
Wheels: 4, Brand: Tata

class Vehicle
{
    int wheels = 4;
    void start() { System.out.println("Vehicle starts"); }
}

class Car extends Vehicle
{

Output

Roll  : 21
Name  : Ankit
Marks : 72, 64
Total : 136  Percentage: 68.0
Grade : First class

class Student
{
    int roll = 21;
    String name = "Ankit";
}

class Test extends Student
{

🎤 Viva questions (5)

Q. What is inheritance?: A. Acquiring the properties and methods of one class into another using extends.
Q. Does Java support multiple inheritance with classes?: A. No; a class can extend only one class. Interfaces are used instead.
Q. What is the use of super?: A. To call the parent constructor (super()) or a parent method/field (super.x).
Q. What is method overriding?: A. A child class giving its own version of a parent method with the same signature.
Q. In which order are constructors called in multilevel inheritance?: A. From the top parent class down to the child class.

Practical 9Compulsory

Implementation of interface

Aim: Declare interfaces, implement them in classes and achieve multiple inheritance through interfaces.

QWrite a program to implement an interface.

Showing answer A of 3 · tap A, B or C to see the others

Output

Circle     area =   12.57  perimeter =  12.57
Rectangle  area =   24.00  perimeter =  20.00

interface Shape
{
    double PI = 3.14159;              // public static final by default
    double area();                    // public abstract by default
    double perimeter();
}

class Circle implements Shape

Output

HP-2320: printing the document...
HP-2320: scanning the page...
HP-2320: printing the document...

interface Printable { void print(); }
interface Scannable { void scan(); }

class AllInOne implements Printable, Scannable
{
    String model;
    AllInOne(String model) { this.model = model; }
    public void print() { System.out.println(model + ": printing the document..."); }

Output

--- Payment summary ---
UPI: amount 1200.0, GST 216.0
Card: amount 2500.0, GST 470.0

interface Payment
{
    double amount();
    default double gst() { return amount() * 0.18; }
    static void header() { System.out.println("--- Payment summary ---"); }
}

class UPI implements Payment

🎤 Viva questions (5)

Q. What is an interface?: A. A reference type with abstract methods and constants that a class implements.
Q. Why are interface methods public?: A. They are public abstract by default, so implementing methods must also be public.
Q. How does Java achieve multiple inheritance?: A. A class can implement more than one interface.
Q. What is the difference between an abstract class and an interface?: A. An abstract class can have state and constructors; a class implements many interfaces but extends one class.
Q. Can we create an object of an interface?: A. No, but an interface reference can point to an object of an implementing class.

Practical 10Compulsory

Built-in packages and user-defined packages

Aim: Import classes from Java packages and create your own package.

Q1Program 1: use built-in packages.

Showing answer A of 3 · tap A, B or C to see the others

Output

sqrt(144)   = 12.0
pow(2, 10)  = 1024.0
max(7, 19)  = 19
Sorted list = [10, 20, 30, 40]
Date        = 28-10-2026
Day         = WEDNESDAY

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collections;

public class Main
{
    public static void main(String[] args)

Output

How many dice rolls? 4
Roll 1: 5
Roll 2: 3
Roll 3: 4
Roll 4: 5
Total = 17

import java.util.Random;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Random r = new Random(7);          // fixed seed: same numbers every run

Output

Notebook -> 25
Pen -> 40
Pencil -> 60
Items in stock: 3
Has Eraser?   : false

import java.util.*;

public class Main
{
    public static void main(String[] args)
    {
        HashMap<String, Integer> stock = new HashMap<>();
        stock.put("Pen", 40);

Q2Program 2: create and use a user-defined package.

Showing answer A of 3 · tap A, B or C to see the others

Output

add(12, 30)        = 42
multiply(6, 7)     = 42
average(4, 8, 15)  = 9.0

// FILE: mypack/Calculator.java
package mypack;

public class Calculator
{
    public int add(int a, int b) { return a + b; }
    public int multiply(int a, int b) { return a * b; }
    public double average(int... nums)

Output

Meera scored 82 -> PASS
Arjun scored 35 -> FAIL

// FILE: college/student/Student.java
package college.student;

public class Student
{
    private String name;
    private int marks;
    public Student(String name, int marks) { this.name = name; this.marks = marks; }

Output

Holder  : Vikas
Balance : 15000.0
PIN 1111 correct? false
PIN 1234 correct? true

// FILE: bank/Account.java
package bank;

public class Account
{
    public String holder = "Vikas";
    protected double balance = 15000;
    double branchCode = 4021;           // default access: only inside package bank

🎤 Viva questions (5)

Q. What is a package?: A. A group of related classes and interfaces, stored in a folder with the same name.
Q. Which package is imported by default?: A. java.lang
Q. How do you compile a class that is in a package?: A. javac -d . FileName.java — -d creates the package folders.
Q. What is the difference between import java.util.* and import java.util.Scanner?: A. The first imports all classes of java.util, the second only Scanner.
Q. What is default (package) access?: A. A member with no modifier is visible only inside its own package.

Practical 11

Exception handling with try, catch and finally

Aim: Handle run-time errors with try, catch (single and multiple) and finally.

QWrite a program to implement try, catch and finally blocks.

Showing answer A of 3 · tap A, B or C to see the others

Output

Enter two numbers: 20 0
Error: / by zero
finally block: always runs
Program continues normally.

import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter two numbers: ");

Output

Case 1: array index is wrong -> Index 5 out of bounds for length 3
   (finally for case 1)
Case 2: object is null
   (finally for case 2)
Case 3: NumberFormatException -> For input string: "12ab"
   (finally for case 3)

public class Main
{
    static void test(int choice)
    {
        try
        {
            if (choice == 1)
            {

Output

Enter your age: twenty
Please type a number only.
Enter your age: 20
Age accepted: 20

import java.util.InputMismatchException;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);

🎤 Viva questions (5)

Q. What is an exception?: A. An error event at run time that stops the normal flow of the program.
Q. What is the use of finally?: A. It always runs, so it is used to close files, connections etc.
Q. Can we have try without catch?: A. Yes, try with finally only (or try-with-resources).
Q. Why must catch(Exception e) come last?: A. Otherwise the specific catch blocks below it can never be reached (compile error).
Q. Name two unchecked exceptions.: A. ArithmeticException, NullPointerException, ArrayIndexOutOfBoundsException.

Practical 12Compulsory

throw and throws clauses

Aim: Throw exceptions with throw, declare them with throws and create your own exception class.

QWrite a program to implement the throw and throws clauses.

Showing answer A of 3 · tap A, B or C to see the others

Output

Enter two ages: 21 16
Age 21: eligible to vote
Exception: Age 16 is below 18, cannot vote

import java.util.Scanner;

class InvalidAgeException extends Exception
{
    InvalidAgeException(String msg) { super(msg); }
}

public class Main

Output

Withdrawn Rs. 1500.0, balance Rs. 3500.0
Rs. 4200.0 -> Insufficient balance, short by Rs. 700.0
Withdrawn Rs. 3000.0, balance Rs. 500.0

class InsufficientBalanceException extends Exception
{
    InsufficientBalanceException(double need)
    {
        super("Insufficient balance, short by Rs. " + need);
    }
}

Output

Count 1
Count 2
Count 3
Marks: 85
Caught: Marks must be 0-100, got 140

public class Main
{
    static void slowCount(int n) throws InterruptedException
    {
        for (int i = 1; i <= n; i++)
        {
            System.out.println("Count " + i);
            Thread.sleep(200);          // may throw InterruptedException

🎤 Viva questions (5)

Q. What is the difference between throw and throws?: A. throw throws an exception object inside a method; throws declares possible exceptions in the method signature.
Q. How do you create a user-defined exception?: A. Create a class that extends Exception (checked) or RuntimeException (unchecked).
Q. What is a checked exception?: A. An exception checked at compile time that must be caught or declared, e.g. IOException.
Q. Can we throw more than one exception with throws?: A. Yes, separated by commas: throws IOException, SQLException.
Q. What does super(msg) do in an exception class?: A. It stores the message so getMessage() can return it.

Practical 13Compulsory

Multithreading

Aim: Create threads by extending Thread and implementing Runnable, use sleep, join, priority and synchronization.

QWrite a program to implement multithreading.

Showing answer A of 3 · tap A, B or C to see the others

Output

Even: 2
Odd : 1
Even: 4
Odd : 3
Even: 6
Odd : 5
Even: 8
Odd : 7
Even: 10
Odd : 9
Both threads finished.

class EvenThread extends Thread
{
    public void run()
    {
        for (int i = 2; i <= 10; i += 2)
        {
            System.out.println("Even: " + i);
            try { Thread.sleep(300); } catch (InterruptedException e) { }

Output

Downloader (priority 10) step 1
Downloader (priority 10) step 2
Downloader (priority 10) step 3
Printer (priority 1) step 1
Printer (priority 1) step 2
Printer (priority 1) step 3
isAlive after join: false

class Task implements Runnable
{
    public void run()
    {
        Thread t = Thread.currentThread();
        for (int i = 1; i <= 3; i++)
        {
            System.out.println(t.getName() + " (priority " + t.getPriority() + ") step " + i);

Output

Expected count : 30000
Actual count   : 30000

class Counter
{
    private int count = 0;
    synchronized void increment() { count++; }
    int get() { return count; }
}

public class Main

🎤 Viva questions (5)

Q. What are the two ways to create a thread?: A. Extend the Thread class, or implement the Runnable interface.
Q. What is the difference between start() and run()?: A. start() creates a new thread that calls run(); calling run() directly runs it in the current thread.
Q. What does join() do?: A. Makes the current thread wait until the other thread finishes.
Q. What is synchronization?: A. Allowing only one thread at a time to access shared code/data, to avoid wrong results.
Q. Name the states of a thread.: A. New, Runnable, Running, Blocked/Waiting, Terminated (Dead).

Practical 14Compulsory

Design a form using AWT components

Aim: Use Frame, Label, TextField, TextArea, Checkbox, CheckboxGroup, Choice, List and Button to design a form.

QWrite a program to design any type of form using AWT components.

Showing answer A of 3 · tap A, B or C to see the others

Output

A window titled "Student
Registration" (420 × 420) opens
with:
Name      [ Sneha Patil            ]
Gender    (•) Male   ( ) Female
Branch    [ Computer ▼ ]
Hobbies   [✓] Coding  [ ] Sports
Address   [ Shivaji Nagar, Pune    ]
[ Submit ]  [ Reset ]
Clicking × closes the window.

import java.awt.*;
import java.awt.event.*;

public class Main extends Frame
{
    Main()
    {
        setTitle("Student Registration");

Output

A window titled "Course Feedback"
opens. The components flow from left
to right:
Your name: [Rahul]
Subjects you liked: a list box with
Java Programming and DBMS
highlighted, Data Structures and
Computer Networks not selected
Rating: (•) Good ( ) Average ( )
Poor
a text area "Labs were very useful."
[ Send feedback ]

import java.awt.*;
import java.awt.event.*;

public class Main
{
    public static void main(String[] args)
    {
        Frame f = new Frame("Course Feedback");

Output

A small window titled "Login" opens.
At the top: "Ananda College Portal".
Below, a 3 × 2 grid:
Username:      [admin ]
Password:      [******]
[ ] Remember me   [ Login ]

import java.awt.*;
import java.awt.event.*;

public class Main extends Frame
{
    Main()
    {
        super("Login");

🎤 Viva questions (5)

Q. What is AWT?: A. Abstract Window Toolkit — Java's original package (java.awt) for GUI components.
Q. What is the difference between Frame and Panel?: A. Frame is a top-level window with title bar; Panel is a container placed inside another container.
Q. How do you make radio buttons in AWT?: A. Put Checkbox objects in a CheckboxGroup.
Q. What is the default layout of Frame and Panel?: A. Frame: BorderLayout; Panel: FlowLayout.
Q. Why does an AWT Frame not close on ×?: A. We must add a WindowListener and call dispose() or System.exit() in windowClosing().

Practical 15

Menu bar with menu items and sub-menu items

Aim: Create a menu bar with menus, menu items, a sub-menu, separators and shortcut keys.

QWrite a program to create a menu bar with various menu items and sub-menu items.

Showing answer A of 3 · tap A, B or C to see the others

Output

A window titled "AWT Menu Demo"
opens with a menu bar: File  Edit
Help.
File contains: New, Open, Open
Recent ▸ (notes.txt, marks.csv),
———, Exit.
Edit contains: Cut, Copy, Paste, ✓
Word wrap.
Help contains: About.
The text area says "Click File >
Open Recent to see the sub-menu."

import java.awt.*;
import java.awt.event.*;

public class Main extends Frame
{
    Main()
    {
        super("AWT Menu Demo");

Output

A window titled "Notepad Menu" opens
with the File menu already dropped
down:
New        Ctrl-N
Save       Ctrl-S
Export as  ▸   (PDF, Word)
————————
Exit
The menu bar also has "Format" with
☑ Bold and ☐ Italic.

import java.awt.event.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Notepad Menu");

Output

A window titled "Colour Menu" with a
menu "Colour" (Red, Green, Blue,
———, Light shades ▸ Pink).
Blue has been chosen, so the whole
window area is blue with white text
"Background: Blue".
Choosing Red or Green changes the
colour; Light shades ▸ Pink makes it
pink.

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Colour Menu");

🎤 Viva questions (5)

Q. Which classes are used to create a menu in AWT?: A. MenuBar, Menu, MenuItem, CheckboxMenuItem.
Q. How is a sub-menu created?: A. By adding a Menu (or JMenu) object to another Menu.
Q. Which method attaches a menu bar to a JFrame?: A. setJMenuBar() (setMenuBar() for an AWT Frame).
Q. What is a mnemonic?: A. An Alt-key shortcut that opens a menu, e.g. Alt+F.
Q. What is an accelerator?: A. A key combination like Ctrl+S that runs a menu item directly.

Practical 16

BorderLayout with four buttons using Swing

Aim: Place buttons "left", "right", "top", "bottom" (and centre) with BorderLayout.

QWrite a program to demonstrate the use of border layout using four buttons labelled "left", "right", "top" and "bottom".

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "Border Layout":
┌────────── top ──────────┐
│ left │   (empty)   │ right │
└───────── bottom ────────┘
top and bottom stretch across the
width; left and right fill the
height between them.

import java.awt.BorderLayout;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Border Layout");

Output

Window "Border Layout with gaps":
buttons top (full width), bottom
(full width), left and right, with
10 px gaps.
The centre shows "Click any button"
in bold. Clicking "left" changes it
to "You clicked: left".

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Border Layout with gaps");

Output

Window "Nested Border Layout": at
the top a small "top" button and the
text "Page title" on the left;
tall "left" and "right" buttons at
the sides; a text area in the middle
with "Main content goes in the
CENTER region.";
a small "bottom" button at the
bottom-right.

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Nested Border Layout");

🎤 Viva questions (5)

Q. What are the five regions of BorderLayout?: A. NORTH, SOUTH, EAST, WEST, CENTER.
Q. What happens if two components are added to the same region?: A. Only the last one is shown.
Q. Which region gets the extra space?: A. CENTER.
Q. What is the default layout of JFrame?: A. BorderLayout.
Q. What do the two numbers in new BorderLayout(10, 10) mean?: A. Horizontal and vertical gaps between regions.

Practical 17Compulsory

Calculator using GridLayout (Swing)

Aim: Arrange calculator buttons with GridLayout and handle their clicks.

QWrite a program to create a calculator using grid layout.

Showing answer A of 3 · tap A, B or C to see the others

Output

A window titled "Calculator": a
large display at the top showing 48
(the demo 12 * 4 =),
and below it a 4 × 4 grid of
buttons:
7 8 9 /
4 5 6 *
1 2 3 -
C 0 = +
Clicking digits and operators works
like a normal calculator; C clears;
dividing by 0 shows "Error".

import java.awt.*;
import javax.swing.*;

public class Main extends JFrame
{
    JTextField display = new JTextField("0");
    double first = 0;
    String op = "";

Output

Window "Two-number Calculator" laid
out as a 5 × 2 grid:
First number  [36]
Second number [8]
[ Add ] [ Subtract ]
[ Multiply ] [ Divide ]
  Result: 44.0
(Add was clicked; Divide would show
4.5.)

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Two-number Calculator");

Output

Window "Scientific Keys": a text
field with 16 at the top, a 2 × 3
grid of buttons
[sqrt] [square] [cube]
[log10] [sin(deg)] [1/x]
and at the bottom "sqrt(16.0) =
4.0000".

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Scientific Keys");

🎤 Viva questions (5)

Q. What is GridLayout?: A. A layout that arranges components in a grid of equal-size rows and columns.
Q. What do the parameters of GridLayout(4, 4, 6, 6) mean?: A. rows, columns, horizontal gap, vertical gap.
Q. Which listener handles a button click?: A. ActionListener, method actionPerformed(ActionEvent e).
Q. Why is the display text field set not editable?: A. So the user can enter numbers only through the buttons.
Q. How do you convert a text field value into a number?: A. Double.parseDouble(field.getText()) or Integer.parseInt().

Practical 18

JComboBox in a JFrame

Aim: Show a list of choices with JComboBox and respond to the selected item.

QWrite a program to demonstrate the use of JComboBox in a JFrame.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "States": "State:"
[Maharashtra ▼] and the label
"Capital of Maharashtra is Mumbai".
Choosing Karnataka changes the label
to "Capital of Karnataka is
Bengaluru".

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        String[] states = {"Maharashtra", "Gujarat", "Karnataka", "Tamil Nadu", "Madhya Pradesh"};

Output

Window "Programming Languages": an
editable combo box showing "Python",
buttons [Add] [Remove] and the label
"Items: 4".
The drop-down now lists C, C++,
Java, Python. Remove deletes the
selected language.

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Programming Languages");

Output

Window "Course and Subject" (3 × 2
grid):
Course     [BCA ▼]
Subject    [PHP ▼]
You chose  PHP
Changing Course to MCA reloads
Subject with Advanced Java, Machine
Learning, Cloud Computing.

import java.awt.*;
import java.util.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {

🎤 Viva questions (5)

Q. What is JComboBox?: A. A Swing component that combines a drop-down list with an optional text field.
Q. How do you get the selected item?: A. getSelectedItem() (or getSelectedIndex() for its position).
Q. How do you add and remove items?: A. addItem(), removeItem(), removeItemAt(), removeAllItems().
Q. What does setEditable(true) do?: A. Lets the user type a value that is not in the list.
Q. Which listener is used for JComboBox selection?: A. ActionListener (or ItemListener).

Practical 19

JTree and JTable

Aim: Show hierarchical data with JTree and tabular data with JTable.

Q1Program 1: demonstrate the use of JTree.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "College Tree" shows:
Polytechnic
  ▾ Computer    First Year    Second
  Year    Third Year
  ▸ Information Technology
  Mechanical
Clicking ▸ Information Technology
opens Second Year and Third Year.

import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;

public class Main
{
    public static void main(String[] args)
    {
        DefaultMutableTreeNode college = new DefaultMutableTreeNode("Polytechnic");

Output

Window "Syllabus Tree" with all
nodes open:
Java
  Basics: Variables, Operators,
  Loops
  OOP: Class, Inheritance, Interface
  GUI: AWT, Swing
"Inheritance" is highlighted and the
status bar reads "Selected:
Inheritance   (level 2)".

import java.awt.BorderLayout;
import javax.swing.*;
import javax.swing.tree.*;

public class Main
{
    public static void main(String[] args)
    {

Output

Window "Folder Tree": a text field
and an [Add folder] button at the
top; below, the tree
My Files
  ▾ Practicals    Java    C++
  Notes
Select a folder, type a name and
click Add folder to create a
sub-folder inside it.

import java.awt.BorderLayout;
import javax.swing.*;
import javax.swing.tree.*;

public class Main
{
    public static void main(String[] args)
    {

Q2Program 2: demonstrate the use of JTable.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "Marks Table" with a grid:
Roll | Name   | Java | DBMS | OS
1    | Aarav  | 78   | 82   | 69
2    | Bhavna | 88   | 75   | 91
3    | Chetan | 64   | 70   | 58
4    | Diya   | 92   | 89   | 85
5    | Eshan  | 55   | 61   | 73
Cells can be clicked and edited;
columns can be resized by dragging
the header.

import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        String[] cols = {"Roll", "Name", "Java", "DBMS", "OS"};
        Object[][] rows = {

Output

Window "Bill Table":
Item       | Qty | Price | Amount
Notebook   | 4   | 45.0  | 180.0
Pen        | 10  | 12.0  | 120.0
Calculator | 1   | 650.0 | 650.0
Bottom line: "Rows: 3     Total: Rs.
950.0"

import java.awt.BorderLayout;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class Main
{
    public static void main(String[] args)
    {

Output

Window "Employees" with columns Emp
ID, Name, Department, Salary and 4
rows.
Row 103 | Nisha | IT | 56000 is
highlighted and the bottom line says
"Nisha works in IT and earns Rs.
56000".

import java.awt.BorderLayout;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        String[] cols = {"Emp ID", "Name", "Department", "Salary"};

🎤 Viva questions (5)

Q. What is JTree used for?: A. To show data in a hierarchy (parent and child nodes), like folders.
Q. Which class creates a tree node?: A. DefaultMutableTreeNode.
Q. Why is a JTable placed inside a JScrollPane?: A. To show the column headers and allow scrolling.
Q. What is DefaultTableModel?: A. A table model that lets you add, remove and change rows at run time.
Q. How do you read a cell value from a JTable?: A. table.getValueAt(row, column).

Practical 20Compulsory

Key events and mouse events

Aim: Handle keyboard and mouse events with KeyListener, MouseListener and MouseMotionListener.

Q1Program 1: demonstrate key events.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "Key Events" with a text
field and three labels.
Typing "J" with Shift shows: Typed:
J   Pressed: J  (code 74)
Released: J
Pressing Shift alone shows: Pressed:
Shift  (code 16) — no "Typed" event
for Shift.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Main extends JFrame implements KeyListener
{
    JTextField input = new JTextField(20);
    JLabel typed = new JLabel("Typed: ");

Output

Window "Arrow Keys": text "Use arrow
keys.  Box at (140, 80)" at the top
and a blue 40 × 40 square.
Each arrow key moves the square 10
pixels and the coordinates in the
text change.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Main extends JPanel
{
    int x = 140, y = 80;

Output

Window "Live Counter": a text area
with "Java makes GUI events easy"
and below it
"Characters: 26   Words: 5". The
numbers change with every key;
pressing Enter adds "(new line)".

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {

Q2Program 2: demonstrate mouse events.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "Mouse Events": a light blue
area with the status bar "Move or
click the mouse inside the window".
When the mouse enters, the area
turns light green; moving shows
"Moving at (x, y)";
clicking shows "Clicked at (x, y),
clicks: 1"; leaving turns it light
blue again.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Main extends JFrame implements MouseListener, MouseMotionListener
{
    JLabel status = new JLabel(" Move or click the mouse inside the window");
    JPanel area = new JPanel();

Output

Window "Mouse Paint": white area
with the hint "Drag the mouse to
draw" and a green wavy line.
Pressing and dragging the mouse
draws new green lines wherever you
move.

import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import javax.swing.*;

public class Main extends JPanel
{
    ArrayList<Point> points = new ArrayList<>();

Output

Window "Click Circles": three red
numbered circles (1, 2, 3) and the
line
"Double-click: add circle
Right-click: clear   Circles: 3".
Each double-click adds a new
numbered circle; a right-click
removes all of them.

import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import javax.swing.*;

public class Main extends JPanel
{
    ArrayList<Point> dots = new ArrayList<>();

🎤 Viva questions (5)

Q. Which methods does KeyListener have?: A. keyPressed(), keyReleased(), keyTyped().
Q. Which methods does MouseListener have?: A. mouseClicked(), mousePressed(), mouseReleased(), mouseEntered(), mouseExited().
Q. What is an adapter class?: A. A class with empty listener methods, so you override only the ones you need (KeyAdapter, MouseAdapter).
Q. Which listener gives mouseMoved and mouseDragged?: A. MouseMotionListener.
Q. What is the difference between getKeyChar() and getKeyCode()?: A. getKeyChar() gives the typed character; getKeyCode() gives the virtual key code (VK_...).

Practical 21Compulsory

Action events using Swing components

Aim: Handle ActionEvent from JButton, JTextField, JCheckBox and JRadioButton.

QWrite a program to demonstrate action events in a frame using Swing components.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "Login":
Username [student]
Password [•••••••]
[ Login ] [ Clear ]        Login
  successful   (green)
A wrong password shows "Wrong
username or password" in red; Clear
empties the fields.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Main extends JFrame implements ActionListener
{
    JTextField user = new JTextField(12);
    JPasswordField pass = new JPasswordField(12);

Output

Window "Pizza Order":
Size: ( ) Small Rs. 150   (•) Medium
Rs. 250   ( ) Large Rs. 350
Toppings: [✓] Extra cheese +40   [ ]
Olives +30
[ Calculate bill ]
Total bill: Rs. 290

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Pizza Order");

Output

Window "Temperature Converter":
"Celsius: [37] [°C → °F]" and the
result "37.0 °C = 98.6 °F".
Typing another value and pressing
Enter or clicking the button updates
the result.

import java.awt.*;
import javax.swing.*;

public class Main
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Temperature Converter");

🎤 Viva questions (5)

Q. Which interface handles action events?: A. ActionListener, with the method actionPerformed(ActionEvent e).
Q. Which components generate ActionEvent?: A. JButton, JTextField (on Enter), JCheckBox, JRadioButton, JMenuItem, JComboBox.
Q. What does e.getSource() return?: A. The component object that generated the event.
Q. What is getActionCommand()?: A. The command string of the event, by default the button text.
Q. Why use ButtonGroup?: A. To make radio buttons mutually exclusive.

Practical 22

Text events on text components

Aim: React to every change in a text component using TextListener (AWT) and DocumentListener (Swing).

QWrite a program to demonstrate text events on text components.

Showing answer A of 3 · tap A, B or C to see the others

Output

Window "Text Event":
[Hello MSBTE]
You typed: Hello MSBTE
Length: 11
Both labels update with every letter
typed or deleted.

import java.awt.*;
import java.awt.event.*;

public class Main extends Frame implements TextListener
{
    TextField tf = new TextField(20);
    Label echo = new Label("You typed: ");
    Label len = new Label("Length: 0");

Output

Window "Password Strength":
Password [•••••••••]
Strength  Strong   (green)
While typing, the label changes Weak
(red) → Medium (orange) → Strong
(green).

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;

public class Main
{
    static String strength(String p)
    {

Output

Window "City Search": the search box
shows "na"; the list shows Nagpur,
Nashik, Nanded, Jalna;
the bottom line says "4 of 10
cities". Deleting the text shows all
10 cities again.

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;

public class Main
{
    public static void main(String[] args)
    {

🎤 Viva questions (5)

Q. Which listener handles TextEvent?: A. TextListener, with the method textValueChanged(TextEvent e).
Q. Which components generate TextEvent?: A. AWT TextField and TextArea.
Q. How do you detect text changes in a Swing JTextField?: A. Add a DocumentListener to its Document.
Q. What are the methods of DocumentListener?: A. insertUpdate(), removeUpdate(), changedUpdate().
Q. What is the difference between ActionEvent and TextEvent on a text field?: A. ActionEvent comes only on Enter; TextEvent comes on every change.

Practical 23

Retrieve host name and IP address using InetAddress

Aim: Use the InetAddress class to find the name and IP address of the local machine and of other hosts.

QWrite a program to retrieve the host name and IP address using the InetAddress class.

Showing answer A of 3 · tap A, B or C to see the others

Output

Local host     : LAB-PC-12/192.168.1.12
Host name      : LAB-PC-12
IP address     : 192.168.1.12
Loopback name  : localhost
Loopback IP    : 127.0.0.1
Is loopback?   : true

import java.net.InetAddress;
import java.net.UnknownHostException;

public class Main
{
    public static void main(String[] args)
    {
        try

Output

Enter a host name: localhost
Addresses of localhost:
  127.0.0.1  (IPv4)

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args)
    {

Output

127.0.0.1       -> loopback
192.168.1.12    -> private (LAN)
8.8.8.8         -> public
224.0.0.5       -> multicast

import java.net.InetAddress;

public class Main
{
    public static void main(String[] args) throws Exception
    {
        byte[][] ips = { {127, 0, 0, 1}, {(byte) 192, (byte) 168, 1, 12}, {8, 8, 8, 8}, {(byte) 224, 0, 0, 5} };
        for (byte[] ip : ips)

🎤 Viva questions (5)

Q. What is InetAddress?: A. A class in java.net that represents an IP address (and its host name).
Q. How do you get the IP address of your own computer?: A. InetAddress.getLocalHost().getHostAddress().
Q. Which exception do InetAddress methods throw?: A. UnknownHostException.
Q. What is the loopback address?: A. 127.0.0.1 (localhost) — it always means the same machine.
Q. What is DNS?: A. Domain Name System — it converts host names into IP addresses.

Practical 24Compulsory

Methods of the URL class and the URLConnection class

Aim: Split a URL into its parts and use URLConnection to read header information and content.

QWrite a program to demonstrate the use of the URL and URLConnection classes and their methods.

Showing answer A of 3 · tap A, B or C to see the others

Output

URL          : https://www.msbte.org.in:443/results/index.php?seat=245781&exam=W26#top
Protocol     : https
Host         : www.msbte.org.in
Port         : 443
Default port : 443
Path         : /results/index.php
File         : /results/index.php?seat=245781&exam=W26
Query        : seat=245781&exam=W26
Ref (anchor) : top
Authority    : www.msbte.org.in:443

import java.net.URI;
import java.net.URL;

public class Main
{
    public static void main(String[] args) throws Exception
    {
        URL u = new URI("https://www.msbte.org.in:443/results/index.php?seat=245781&exam=W26#top").toURL();

Output

--- WebServer window ---
Web server running on http://localhost:8080/

--- Main window ---
Content type   : text/html; charset=UTF-8
Content length : 101 bytes
Date           : received
Server header  : text/html; charset=UTF-8
Response code  : 200
Message        : OK

// FILE: WebServer.java
import com.sun.net.httpserver.HttpServer;
import java.io.OutputStream;
import java.net.InetSocketAddress;

// A tiny local web page so the program can be tested without internet.
public class WebServer
{

Output

--- WebServer window ---
Web server running on http://localhost:8080/

--- Main window ---
Reading http://localhost:8080/
<html><head><title>JPR Lab</title></head><body><h1>Hello from the local web server</h1></body></html>
Lines: 1, characters: 101

// FILE: WebServer.java
import com.sun.net.httpserver.HttpServer;
import java.io.OutputStream;
import java.net.InetSocketAddress;

// A tiny local web page so the program can be tested without internet.
public class WebServer
{

🎤 Viva questions (5)

Q. What is a URL?: A. Uniform Resource Locator — the address of a resource on the internet.
Q. Name four methods of the URL class.: A. getProtocol(), getHost(), getPort(), getFile() (also getPath(), getQuery(), getRef()).
Q. What does getPort() return when no port is given?: A. -1 (getDefaultPort() gives 80/443).
Q. How do you get a URLConnection object?: A. By calling openConnection() on a URL object.
Q. What is the difference between URL and URLConnection?: A. URL only describes the address; URLConnection actually connects and reads/writes data.

Practical 25Compulsory

Connection-oriented communication using sockets (TCP)

Aim: Write a server with ServerSocket and a client with Socket that exchange messages over TCP.

QWrite a program to demonstrate connection-oriented communication using sockets.

Showing answer A of 3 · tap A, B or C to see the others

Output

--- Server window ---
Server waiting on port 5000...
Client connected from 127.0.0.1
Client says: Priya Deshmukh
Server closed

--- Client window ---
Connected to server
Enter your name: Priya Deshmukh
Server replied: Hello Priya Deshmukh, welcome to the JPR server!

// FILE: Server.java
import java.io.*;
import java.net.*;

public class Server
{
    public static void main(String[] args) throws IOException
    {

Output

--- Server window ---
Square server started on port 5001
Received 7, sending 49
Received 12, sending 144
Client sent 0, connection closed

--- Client window ---
Enter a number (0 to stop): 7
Square from server = 49
Enter a number (0 to stop): 12
Square from server = 144
Enter a number (0 to stop): 0
Client finished

// FILE: Server.java
import java.io.*;
import java.net.*;

public class Server
{
    public static void main(String[] args) throws IOException
    {

Output

--- Server window ---
Chat server ready
Client: hello server
Client: java sockets
Client: bye

--- Client window ---
You: hello server
Server: Server got 12 characters: HELLO SERVER
You: java sockets
Server: Server got 12 characters: JAVA SOCKETS
You: bye
Server: Bye! Have a nice day.

// FILE: Server.java
import java.io.*;
import java.net.*;

public class Server
{
    public static void main(String[] args) throws IOException
    {

🎤 Viva questions (5)

Q. What is a socket?: A. One end-point of a two-way connection between two programs on a network (IP + port).
Q. Which classes are used for TCP in Java?: A. ServerSocket (server) and Socket (client).
Q. What does accept() do?: A. Waits for a client and returns a Socket connected to it.
Q. What is a port number?: A. A number (0–65535) that identifies a program/service on a computer.
Q. Why is TCP called connection-oriented?: A. A connection is set up before data is sent, and delivery and order are guaranteed.

Practical 26

Sending and receiving data using datagrams (UDP)

Aim: Use DatagramSocket and DatagramPacket to send and receive messages without a connection.

QWrite a program to send and receive data through datagrams.

Showing answer A of 3 · tap A, B or C to see the others

Output

--- Receiver window ---
Receiver waiting on port 6000...
Received: Practical 26 works
From 127.0.0.1 port 59684

--- Sender window ---
Message to send: Practical 26 works
Sent 18 bytes

// FILE: Receiver.java
import java.net.*;

public class Receiver
{
    public static void main(String[] args) throws Exception
    {
        DatagramSocket ds = new DatagramSocket(6000);

Output

--- Receiver window ---
Greeting server on UDP 6001
Request from client: Rohan
Request from client: Sakshi

--- Sender window ---
Name 1: Rohan
Reply: Namaste Rohan! (5 letters)
Name 2: Sakshi
Reply: Namaste Sakshi! (6 letters)

// FILE: Receiver.java
import java.net.*;

public class Receiver
{
    public static void main(String[] args) throws Exception
    {
        try (DatagramSocket ds = new DatagramSocket(6001))

Output

--- Receiver window ---
Sum server ready
Numbers received: 15 25 35 45
Sum 120 sent back

--- Sender window ---
Enter numbers separated by spaces: 15 25 35 45
Sum from receiver = 120

// FILE: Receiver.java
import java.net.*;

public class Receiver
{
    public static void main(String[] args) throws Exception
    {
        DatagramSocket ds = new DatagramSocket(6002);

🎤 Viva questions (5)

Q. What is a datagram?: A. An independent, self-contained packet sent over UDP without a connection.
Q. Which classes are used for UDP?: A. DatagramSocket and DatagramPacket.
Q. What is the difference between TCP and UDP?: A. TCP is connection-oriented and reliable; UDP is connectionless, faster, but delivery is not guaranteed.
Q. Which method waits for a packet?: A. DatagramSocket.receive(packet).
Q. Give one use of UDP.: A. Video/voice streaming, online games, DNS.

Practical 27Compulsory

Create a sample database and connect to it (JDBC)

Aim: Create a MySQL database and table from Java and connect using the JDBC driver.

QWrite a program to create a sample database in any DBMS and connect to it.

Showing answer A of 3 · tap A, B or C to see the others

Install MySQL Server (or XAMPP, which includes MySQL/MariaDB) and note the root password.
Download "Connector/J" (mysql-connector-j-*.jar) from dev.mysql.com/downloads/connector/j (Platform Independent).
Put the jar next to your program (or add it to the IDE build path).
Compile: javac Main.java
Run on Windows: java -cp .;mysql-connector-j-9.1.0.jar Main (on Linux/Mac use : instead of ;)

Output

Connected successfully!
Database product : MySQL
Driver           : MySQL Connector/J
Driver version   : mysql-connector-j-8.4.0 (Revision: 1c3f5c149e0bfe31c7fbeb24e2d260cd890972c4)
User             : root@localhost

import java.sql.*;

public class Main
{
    public static void main(String[] args)
    {
        String url = "jdbc:mysql://localhost:3306/";
        try (Connection con = DriverManager.getConnection(url, "root", "root"))

Output

Database jpr_college ready
Table student created
Columns:
  roll  int(11)
  name  varchar(40)
  branch  varchar(10)
  percentage  double

import java.sql.*;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        try (Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/", "root", "root");
             Statement st = con.createStatement())

Output

Connected to jpr_college
5 sample rows inserted
Roll  Name              Branch  %
1     Aarav Kulkarni    CO      78.5
2     Bhavna Jadhav     IF      84.2
3     Chetan More       CO      66.0
4     Diya Shinde       AI      91.4
5     Eshan Pawar       IF      59.8

import java.sql.*;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        String url = "jdbc:mysql://localhost:3306/jpr_college";
        try (Connection con = DriverManager.getConnection(url, "root", "root");

🎤 Viva questions (5)

Q. What is JDBC?: A. Java Database Connectivity — an API (java.sql) to connect Java programs to databases.
Q. What are the steps to connect to a database?: A. Load the driver, get a Connection, create a Statement, execute SQL, process the ResultSet, close.
Q. What is a JDBC driver?: A. Software (a JAR) that converts JDBC calls into the database's own protocol, e.g. MySQL Connector/J.
Q. Which driver type is MySQL Connector/J?: A. Type 4 (pure Java, thin driver).
Q. What is the difference between executeQuery and executeUpdate?: A. executeQuery runs SELECT and returns a ResultSet; executeUpdate runs INSERT/UPDATE/DELETE/DDL and returns a row count.

Practical 28Compulsory

Database operations: insert, update and delete records

Aim: Insert, update and delete records in the student table using JDBC.

QWrite a program to insert, update and delete a record in a database.

Showing answer A of 3 · tap A, B or C to see the others

Output

Inserted rows: 1
Updated rows : 1
Deleted rows : 1
Table now:
  1 | Aarav Kulkarni | CO | 78.5
  2 | Bhavna Jadhav | IF | 84.2
  3 | Chetan More | CO | 70.5
  4 | Diya Shinde | AI | 91.4
  6 | Farhan Shaikh | CO | 72.6

import java.sql.*;

public class Main
{
    static void show(Statement st) throws SQLException
    {
        ResultSet rs = st.executeQuery("SELECT * FROM student ORDER BY roll");
        while (rs.next())

Output

1.Insert 2.Update % 3.Delete 4.Count 5.Exit : 1
Roll name(one word) branch percentage: 7 Gauri CO 81.3
Record inserted
1.Insert 2.Update % 3.Delete 4.Count 5.Exit : 2
Roll and new percentage: 7 83.0
Record updated
1.Insert 2.Update % 3.Delete 4.Count 5.Exit : 3
Roll to delete: 99
Roll not found
1.Insert 2.Update % 3.Delete 4.Count 5.Exit : 4
Total students: 6
1.Insert 2.Update % 3.Delete 4.Count 5.Exit : 5

import java.sql.*;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        Scanner sc = new Scanner(System.in);

Output

Before:
  rows = 5, average % = 75.98
Error: Duplicate entry '1' for key 'PRIMARY'
Rolled back - the update was undone too
After:
  rows = 5, average % = 75.98

import java.sql.*;

public class Main
{
    static double total(Statement st) throws SQLException
    {
        ResultSet rs = st.executeQuery("SELECT COUNT(*), ROUND(AVG(percentage), 2) FROM student");
        rs.next();

🎤 Viva questions (5)

Q. Which method is used for INSERT, UPDATE and DELETE?: A. executeUpdate().
Q. What does executeUpdate() return?: A. The number of rows affected.
Q. What is auto-commit?: A. By default every SQL statement is saved (committed) immediately.
Q. What is rollback?: A. Undoing the uncommitted changes of a transaction.
Q. What is SQL injection?: A. An attack where user input changes the SQL command; avoid it with PreparedStatement.

Practical 29

PreparedStatement

Aim: Use PreparedStatement with ? parameters for insert, update, select and batch operations.

QWrite a program to demonstrate the use of PreparedStatement.

Showing answer A of 3 · tap A, B or C to see the others

Output

How many students to add? 2
Roll: 6
Full name: Gauri D'Souza
Branch: CO
Percentage: 81.3
1 row inserted
Roll: 7
Full name: Harsh Wagh
Branch: AI
Percentage: 74.9
1 row inserted

import java.sql.*;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        Scanner sc = new Scanner(System.in);

Output

Branch and minimum percentage: IF 60
  2  Bhavna Jadhav  84.2
Roll and new branch: 3 IF
1 row updated

import java.sql.*;
import java.util.Scanner;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        Scanner sc = new Scanner(System.in);

Output

Statements in batch: 3
  1  Aarav Kulkarni  80.0
  2  Bhavna Jadhav  84.2
  3  Chetan More  68.0
  4  Diya Shinde  91.4
  5  Eshan Pawar  62.8

import java.sql.*;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        Object[][] grace = { {1, 1.5}, {3, 2.0}, {5, 3.0} };       // roll, grace marks
        try (Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jpr_college", "root", "root");

🎤 Viva questions (5)

Q. What is PreparedStatement?: A. A precompiled SQL statement with ? parameters (sub-interface of Statement).
Q. Why is PreparedStatement better than Statement?: A. Faster for repeated SQL and safe from SQL injection.
Q. How are parameters set?: A. With setInt(), setString(), setDouble()… using the parameter index starting at 1.
Q. What is CallableStatement?: A. Used to call stored procedures in the database.
Q. What do addBatch() and executeBatch() do?: A. Collect several executions and send them together.

Practical 30Compulsory

Retrieve data using the ResultSet interface and its navigation methods

Aim: Read records with ResultSet and move through them with next, previous, first, last, absolute and relative.

QWrite a program to retrieve data using the ResultSet interface (navigation methods).

Showing answer A of 3 · tap A, B or C to see the others

Output

first()        -> row 1: 1 Aarav Kulkarni (78.5%)
last()         -> row 5: 5 Eshan Pawar (59.8%)
previous()     -> row 4: 4 Diya Shinde (91.4%)
absolute(2)    -> row 2: 2 Bhavna Jadhav (84.2%)
relative(2)    -> row 4: 4 Diya Shinde (91.4%)
absolute(-2)   -> row 4: 4 Diya Shinde (91.4%)
Forward with next():
  1 Aarav Kulkarni
  2 Bhavna Jadhav
  3 Chetan More
  4 Diya Shinde
  5 Eshan Pawar
isAfterLast(): true

import java.sql.*;

public class Main
{
    static void print(String how, ResultSet rs) throws SQLException
    {
        System.out.printf("%-14s -> row %d: %d %s (%.1f%%)%n", how, rs.getRow(),
                rs.getInt("roll"), rs.getString("name"), rs.getDouble("percentage"));

Output

Columns: 4
roll (INT)          name (VARCHAR)      branch (VARCHAR)    percentage (DOUBLE) 
4                   Diya Shinde         AI                  91.4                
2                   Bhavna Jadhav       IF                  84.2                
1                   Aarav Kulkarni      CO                  78.5                
3                   Chetan More         CO                  66.0                
5                   Eshan Pawar         IF                  59.8                
5 rows, ranked by percentage

import java.sql.*;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        try (Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jpr_college", "root", "root");
             Statement st = con.createStatement();

Output

Row 3 updated
New row inserted
  1 | Aarav Kulkarni | CO | 78.5
  2 | Bhavna Jadhav | IF | 84.2
  3 | Chetan More | CO | 68.5
  4 | Diya Shinde | AI | 91.4
  5 | Eshan Pawar | IF | 59.8
  8 | Isha Bhosale | DS | 88.0

import java.sql.*;

public class Main
{
    public static void main(String[] args) throws SQLException
    {
        try (Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jpr_college", "root", "root");
             Statement st = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE))

🎤 Viva questions (5)

Q. What is a ResultSet?: A. An object that holds the rows returned by a SELECT query, with a cursor pointing to one row.
Q. Where is the cursor at the start?: A. Before the first row; call next() to move to the first row.
Q. Name the navigation methods of ResultSet.: A. next(), previous(), first(), last(), absolute(n), relative(n), beforeFirst(), afterLast().
Q. How do you make a ResultSet scrollable?: A. createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY).
Q. What is ResultSetMetaData?: A. Information about the columns of a ResultSet: count, names, types.

Tick the answers you want in your file

Cover + index

MICRO PROJECT 1✓ Compiled & tested · 126 lines

Mini ATM System

Create a menu-driven ATM for a few bank accounts. The user logs in with account number and PIN, then can check the balance, deposit, withdraw (with a minimum balance and daily limit) and see a mini statement.

ClassesEncapsulationUser-defined exceptionArrayListswitch

Class Account with account number, holder name, PIN and balance (encapsulation)
Login with 3 PIN attempts, then the card is blocked
Deposit, withdraw in multiples of 100, minimum balance Rs. 1000, daily limit Rs. 20,000
User-defined exception InsufficientFundsException (throw / throws)
Mini statement of the last 5 transactions using ArrayList

WHAT YOU SUBMIT

📄 Main.java📄 README.md📄 output screenshot

Main.java126 lines

import java.util.ArrayList;
import java.util.Scanner;

class InsufficientFundsException extends Exception
{
    InsufficientFundsException(String msg) { super(msg); }
}

class Account
{

● Output · real run

===== Welcome to Ananda Bank ATM =====
Enter account number: 1002
Enter PIN: 1111
Wrong PIN (2 attempts left)
Enter PIN: 4321
Hello Rutuja Patil!

1.Balance 2.Deposit 3.Withdraw 4.Mini statement 5.Exit
Choice: 1
Balance: Rs. 4200.00

1.Balance 2.Deposit 3.Withdraw 4.Mini statement 5.Exit

Put your micro project on GitHub

MSBTE asks for a GitHub repository with at least 3 commits and a README. You do this yourself, free:

1Make a free account on github.com (email, password, username).
2Click + → New repository: project name, keep it Public, tick Add a README file, press Create repository.
3Add file → Upload files: drag your code files, message “Add source code”, press Commit changes.
4Upload the output screenshots the same way — that is your 2nd commit.
5Open README.md → pencil (edit): project name, group members, how to run it → Commit changes.
6Copy the repository link from the address bar and put it in your micro project report.

Tip: a free account here shows the full code of every micro project and practical.

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Question papersPrevious Diploma papers for your branch and semester, free to open and download.FREEOpen question papers →Final year projects50 ready projects for Diploma — source code, report, setup and viva help. Read any project's abstract free on WhatsApp first.FREE ABSTRACTSee final year projects →Industrial training45 days, 3 or 6 months — Python, web, Android and more, online or at our office in Nanded, with certificate.See training →

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Java Programming practicals — MSBTE

Set up the Java development environment (command prompt and IDE)

Evaluate different types of expressions

if statements, switch-case and loops (for, while, do..while)

Methods of the String class and the StringBuffer class

Use of arrays and Vectors

Wrapper classes: primitive to object and object to primitive

Different types of constructors

Single inheritance and multilevel inheritance

Implementation of interface

Built-in packages and user-defined packages

Exception handling with try, catch and finally

throw and throws clauses

Multithreading

Design a form using AWT components

Menu bar with menu items and sub-menu items

BorderLayout with four buttons using Swing

Calculator using GridLayout (Swing)

JComboBox in a JFrame

JTree and JTable

Key events and mouse events

Action events using Swing components

Text events on text components

Retrieve host name and IP address using InetAddress

Methods of the URL class and the URLConnection class

Connection-oriented communication using sockets (TCP)

Sending and receiving data using datagrams (UDP)

Create a sample database and connect to it (JDBC)

Database operations: insert, update and delete records

PreparedStatement

Retrieve data using the ResultSet interface and its navigation methods

4 micro projects with full code and output

Put your micro project on GitHub

Save this page — everything till your final year is here