Java Programming (4343203) - Winter 2024 Solution

Question 1(a) [3 marks]

List out various Primitive data types in Java.

Answer: Java offers eight primitive data types for storing simple values directly in memory.

Table: Java Primitive Data Types

Mnemonic: "BILFDC-B: Byte Int Long Float Double Char Boolean types"

Question 1(b) [4 marks]

Explain Structure of Java Program with suitable example.

Answer: Java program structure follows a specific organization with package declarations, imports, class definitions, and methods.

Diagram: Java Program Structure

goat

Code Block:

Java

Mnemonic: "PICOM: Package Import Class Objects Methods in order"

Question 1(c) [7 marks]

List arithmetic operators in Java. Develop a Java program using any three arithmetic operators and show the output of program.

Answer: Arithmetic operators in Java perform mathematical operations on numeric values.

Table: Java Arithmetic Operators

Code Block:

Java

Output:

Values: a = 10, b = 3
Addition (a + b): 13
Multiplication (a * b): 30
Modulus (a % b): 1

Mnemonic: "SAME: Sum Addition Multiply Exponentiation basic operations"

Question 1(c OR) [7 marks]

Write syntax of Java for loop statement. Develop a Java program to find out prime number between 1 to 10.

Answer: The for loop in Java provides a compact way to iterate over a range of values.

Syntax of Java for loop:

for (initialization; condition; increment/decrement) {
    // statements to be executed
}

Code Block:

Java

Output:

Prime numbers between 1 and 10:
2 3 5 7

Mnemonic: "ICE: Initialize, Check, Execute steps of for loop"

Question 2(a) [3 marks]

List the differences between Procedure-Oriented Programming (POP) and Object-Oriented Programming (OOP).

Answer: Procedure-Oriented and Object-Oriented Programming represent fundamentally different programming paradigms.

Table: POP vs OOP

• Organization: POP divides into functions; OOP groups into objects
• Approach: POP follows top-down; OOP follows bottom-up

Mnemonic: "FIOS: Functions In Objects Structure key difference"

Question 2(b) [4 marks]

Explain static keyword with example.

Answer: The static keyword in Java creates class-level members shared across all objects of that class.

Table: Uses of static Keyword

Code Block:

Java

Output:

Static count: 3
c1's instance count: 1
c2's instance count: 1
c3's instance count: 1

Mnemonic: "CBMS: Class-level, Before objects, Memory single, Shared by all"

Question 2(c) [7 marks]

Define Constructor. List types of Constructors. Develop a java code to explain Parameterized constructor.

Answer: A constructor is a special method with the same name as its class, used to initialize objects when created.

Types of Constructors:

Table: Constructor Types in Java

Code Block:

Java

Output:

Student Details:
Name: John
Age: 20
Course: Computer Science
Student Details:
Name: Lisa
Age: 22
Course: Engineering

Mnemonic: "IDCR: Initialize Data Create Ready objects"

Question 2(a OR) [3 marks]

List the basic OOP concepts in Java and explain any one.

Answer: Java implements Object-Oriented Programming through several fundamental concepts.

Table: Basic OOP Concepts in Java

Encapsulation Example:

Java

• Data Hiding: Private variables inaccessible from outside
• Controlled Access: Through public methods (getters/setters)
• Integrity: Data validation ensures correct values

Mnemonic: "EIPA: Encapsulate Inherit Polymorphize Abstract"

Question 2(b OR) [4 marks]

Explain final keyword with example.

Answer: The final keyword in Java restricts changes to entities, creating constants, unchangeable methods, and non-inheritable classes.

Table: Uses of final Keyword

Code Block:

Java

Output:

Speed limit: 120

Mnemonic: "VMP: Variables Methods Permanence with final"

Question 2(c OR) [7 marks]

Write scope of java access modifier. Develop a java code to explain public modifier.

Answer: Access modifiers in Java control visibility and accessibility of classes, methods, and variables.

Table: Java Access Modifier Scope

Code Block:

Java

Output:

Message: Hello, World!
Hello, World!
Modified message

Mnemonic: "CEPM: Class Everywhere Public Most accessible"

Question 3(a) [3 marks]

List out different types of inheritance and explain any one with example.

Answer: Inheritance enables a class to inherit attributes and behaviors from another class.

Table: Types of Inheritance in Java

Single Inheritance Example:

Java

Output:

Name: Max
Breed: Labrador
Max is eating
Max is barking

Mnemonic: "SMHMH: Single Multilevel Hierarchical Multiple Hybrid types"

Question 3(b) [4 marks]

Explain any two String buffer class methods with suitable example.

Answer: StringBuffer is a mutable sequence of characters used for modifying strings, offering various manipulation methods.

Table: Two StringBuffer Methods

Code Block:

Java

Output:

Original: Hello
After append(): Hello World
After appending more: Hello World!2024

New Original: Java
After insert() at beginning: Learn Java
After insert() in middle: Learn Java Programming

Mnemonic: "AIMS: Append Insert Modify StringBuffer"

Question 3(c) [7 marks]

Define Interface. Write a java program to demonstrate multiple inheritance using interface.

Answer: An interface is a contract that declares methods a class must implement, enabling multiple inheritance in Java.

Definition: An interface is a reference type containing only constants, method signatures, default methods, static methods, and nested types with no implementation for abstract methods.

Diagram: Multiple Inheritance using Interfaces

Code Block:

Java

Output:

Device Model: HP LaserJet
HP LaserJet is printing a document
HP LaserJet is scanning a document
Is device Printable? true
Is device Scannable? true

Mnemonic: "IMAC: Interface Multiple Abstract Contract"

Question 3(a OR) [3 marks]

Give differences between Abstract class and Interface.

Answer: Abstract classes and interfaces are both used for abstraction but differ in several key aspects.

Table: Abstract Class vs Interface

• Implementation: Abstract classes can provide partial implementation; interfaces traditionally provide none
• Relationship: Abstract class says "is-a"; interface says "can-do-this"

Mnemonic: "MAPS: Methods Access Purpose Single vs multiple"

Question 3(b OR) [4 marks]

Explain any two String class methods with suitable example.

Answer: The String class offers various methods for string manipulation, comparison, and transformation.

Table: Two String Methods

Code Block:

Java

Output:

substring(0, 4): Java
substring(5): Programming

Comparing strings with equals():
str1.equals(str2): true
str1.equals(str3): false
str1.equals(str4): true

Comparing strings with ==:
str1 == str2: true
str1 == str4: false

Mnemonic: "SEC: Substring Equals Compare string content"

Question 3(c OR) [7 marks]

Explain package and list out steps to create package with suitable example.

Answer: A package in Java is a namespace that organizes related classes and interfaces, preventing naming conflicts.

Steps to Create a Package:

Table: Package Creation Steps

Code Block:

Java

Terminal Commands:

// Step 2: Create directory structure
mkdir -p com/example/math
mkdir -p com/example/app

// Step 3: Place files in appropriate directories
mv Calculator.java com/example/math/
mv CalculatorApp.java com/example/app/

// Step 4: Compile with -d option
javac -d . com/example/math/Calculator.java
javac -d . -cp . com/example/app/CalculatorApp.java

// Step 5: Run with fully qualified name
java com.example.app.CalculatorApp

Output:

Addition: 15
Subtraction: 5
Multiplication: 50
Division: 2.0

Mnemonic: "DISCO: Declare Import Save Compile Organize"

Question 4(a) [3 marks]

List types of errors in Java.

Answer: Java programs can encounter various errors during development and execution.

Table: Types of Errors in Java

• Syntax Errors: Missing semicolons, brackets, or typos
• Semantic Errors: Type mismatches, incompatible operations
• Exceptions: Runtime issues requiring handling

Mnemonic: "CRLLT: Compile Runtime Logical Linkage Thread errors"

Question 4(b) [4 marks]

Explain try catch block with example.

Answer: The try-catch block in Java handles exceptions, allowing programs to continue executing despite errors.

Diagram: Try-Catch Flow

Code Block:

Java

Output:

Exception caught: Index 4 out of bounds for length 3
Array index out of bounds
Finally block executed
Program continues after exception handling

Mnemonic: "TCFE: Try Catch Finally Execute despite errors"

Question 4(c) [7 marks]

List out any four differences between method overloading and overriding. Write a java code to explain method overriding.

Answer: Method overloading and overriding are both forms of polymorphism but differ in functionality and implementation.

Table: Method Overloading vs Overriding

Code Block:

Java

Output:

Animal behavior:
Animal makes a sound
Animal eats food

Dog behavior:
Dog barks
Dog eats meat

Cat behavior:
Cat meows
Animal eats food

Mnemonic: "SBRE: Same-name, Base-derived, Runtime-resolution, Extend functionality"

Question 4(a OR) [3 marks]

List any four inbuilt exceptions.

Answer: Java provides many built-in exception classes that represent various error conditions.

Table: Four Common Inbuilt Exceptions

• Unchecked: Runtime exceptions (don't require explicit handling)
• Hierarchy: All extend from Exception class
• Handling: Can be caught with try-catch blocks

Mnemonic: "NAAC: Null Array Arithmetic Cast common exceptions"

Question 4(b OR) [4 marks]

Explain "throw" keyword with suitable example.

Answer: The throw keyword in Java manually generates exceptions for exceptional conditions in programs.

Table: throw Keyword Usage

Code Block:

Java

Output:

Validating age 20:
Eligible to vote

Validating age 15:
ArithmeticException: Not eligible to vote

Validating age -5:
Exception: Age cannot be negative

Mnemonic: "CET: Create Exception Throw for error handling"

Question 4(c OR) [7 marks]

Compare 'this' keyword Vs 'Super' keyword. Explain super keyword with suitable Example.

Answer: The 'this' and 'super' keywords are used for referencing in Java, with distinct purposes and behaviors.

Table: this vs super Keyword Comparison

Code Block:

Java

Output:

Vehicle constructor called
Car constructor called

Variable access with this and super:
Car brand (this): Toyota
Car color (this): Blue
Vehicle brand (super): Ford
Vehicle color (super): Red

Method call with super:
Car information:
Brand: Ford
Color: Red
Model: Corolla

Mnemonic: "PCIM: Parent Class Inheritance Members with super"

Question 5(a) [3 marks]

List Different Stream Classes.

Answer: Java I/O provides various stream classes for handling input and output operations.

Table: Java Stream Classes

• Byte Streams: Work with binary data (8-bit bytes)
• Character Streams: Work with characters (16-bit Unicode)
• Buffered Streams: Improve performance through buffering

Mnemonic: "BCDOP: Byte Character Data Object Print streams"

Question 5(b) [4 marks]

Write a java program to develop user defined exception for "Divide by zero" error.

Answer: User-defined exceptions allow creating custom exception types for application-specific error conditions.

Code Block:

Java

Output:

10 / 2 = 5.0
Error: Division by zero not allowed
Custom exception stack trace:
DivideByZeroException: Division by zero not allowed
    at CustomExceptionDemo.divide(CustomExceptionDemo.java:19)
    at CustomExceptionDemo.main(CustomExceptionDemo.java:29)
Program continues execution...

Mnemonic: "ETC: Extend Throw Catch custom exceptions"

Question 5(c) [7 marks]

Write a program in Java that reads the content of a file byte by byte and copy it into another file.

Answer: File I/O operations in Java allow reading from and writing to files, with byte streams handling binary data.

Code Block:

Java

Creating source.txt file first:

Java

Output:

Source file created successfully!
Copying file source.txt to destination.txt
File copied successfully!
Total bytes copied: 82
File streams closed successfully

Mnemonic: "CROW: Create Read Open Write file operations"

Question 5(a OR) [3 marks]

List different file operations in Java.

Answer: Java provides comprehensive file handling capabilities through various file operations.

Table: File Operations in Java

• Stream-based: Low-level byte or character streams
• Reader/Writer: Character-oriented file operations
• NIO Package: Enhanced file operations (since Java 7)

Mnemonic: "CRWD: Create Read Write Delete basic operations"

Question 5(b OR) [4 marks]

Write a java program to explain finally block in exception handling.

Answer: The finally block in exception handling ensures code execution regardless of whether an exception occurs.

Diagram: try-catch-finally Flow

Code Block:

Java

Output:

Example 1: No exception
Result: 2
Finally block executed - Example 1

Example 2: Exception caught
Arithmetic exception caught: / by zero
Finally block executed - Example 2

Example 3: Resource management
File not found: nonexistent.txt (No such file or directory)
File resource closed in finally block

Program continues execution...

Mnemonic: "ACRE: Always Cleanup Resources Executes"

Question 5(c OR) [7 marks]

Write a java program to create a file and perform write operation on this file.

Answer: Java provides several ways to create files and write data to them using character or byte streams.

Code Block:

Java

Example output:

File created successfully: sample_data.txt

Enter text to write to file (type 'exit' to finish):
This is line 1 of my file.
This is line 2 with some Java content.
Here is line 3 with more text.
exit

File write operation completed successfully!

Mnemonic: "COWS: Create Open Write Save file operations"