1. Which of the following is OOPs?

Answer:OOP (Object-Oriented Programming) is a programming approach where programs are designed using objects and classes.

The four main concepts of OOP are:

Encapsulation
Abstraction
Inheritance
Polymorphism

Example: A Car object can have data such as color and speed, and methods such as start() and stop().

2. Explain the `class` keyword.

Definition: The class keyword is used to create a class, which acts as a blueprint for creating objects.

Example:

class Student {
    String name;
    int age;
}

Here, Student is a class.

3. Is `String` a primitive data type?

Answer: No. String is not a primitive data type in Java. It is a class (reference data type).

Java primitive data types include:

byte
short
int
long
float
double
char
boolean

Example:

String name = "Harshith";

4. What is the size of `int` in bytes?

Answer: In Java, an int occupies 4 bytes (32 bits).

Range:

-2,147,483,648 to 2,147,483,647

Example:

int age = 20;

5. How is `char` used to store a single character?

Definition: The char data type is used to store one single Unicode character.

It uses single quotes (' ').

Example:

char grade = 'A';
char letter = 'H';

6. Explain the `new` keyword to create an object.

Definition: The new keyword is used to create an object and allocate memory for it.

Example:

Student s = new Student();

Here, new Student() creates an object of the Student class.

7. Explain the statement `Student s = new Student()` to create an object.

Student s = new Student();

Explanation:

Student → Class name
s → Reference variable
new → Allocates memory and creates the object
Student() → Calls the constructor

Example:

class Student {
    String name;
}

Student s = new Student();
s.name = "Harshith";

8. Define Abstraction (showing only required details).

Definition:Abstraction means hiding unnecessary implementation details and showing only the important features to the user.

Real-life example: When driving a car, you use the steering wheel and pedals without knowing how the engine works internally.

Java Example:

abstract class Vehicle {
    abstract void start();
}

9. Define Encapsulation.

Definition:Encapsulation means wrapping data and methods together inside a class and protecting the data using access modifiers such as private.

Example:

class Student {
    private String name;

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

10. What is the `protected` access modifier?

Definition: A protected member can be accessed:

Within the same class
Within the same package
By subclasses, even if they are in different packages

Example:

class Parent {
    protected int age = 50;
}

11. What is the `extends` keyword in Inheritance?

Definition: The extends keyword is used when one class inherits properties and methods from another class.

Example:

class Animal {
    void eat() {
        System.out.println("Eating");
    }
}

class Dog extends Animal {
}

Dog inherits the eat() method from Animal.

12. What is the `implements` keyword?

Definition: The implements keyword is used when a class implements an interface.

Example:

interface Animal {
    void sound();
}

class Dog implements Animal {
    public void sound() {
        System.out.println("Bark");
    }
}

13. Define Polymorphism.

Definition:Polymorphism means one name having many forms.

In Java, there are two main types:

Method Overloading – Compile-time polymorphism
Method Overriding – Runtime polymorphism

Example:

Animal a = new Dog();
a.sound();

The same method can behave differently depending on the object.

14. Explain Method Overloading (compile-time polymorphism).

Definition: Method overloading means having multiple methods with the same name but different parameters.

Example:

class Calculator {
    int add(int a, int b) {
        return a + b;
    }

    int add(int a, int b, int c) {
        return a + b + c;
    }
}

The compiler decides which method to call, so it is called compile-time polymorphism.

15. Explain Method Overriding (runtime polymorphism).

Definition: Method overriding occurs when a child class provides its own implementation of a method already defined in the parent class.

Example:

class Animal {
    void sound() {
        System.out.println("Animal sound");
    }
}

class Dog extends Animal {
    @Override
    void sound() {
        System.out.println("Bark");
    }
}

The method is decided at runtime.

16. Can methods be overloaded by changing the return type?

Answer: No. Methods cannot be overloaded only by changing their return type.

❌ Invalid:

int add(int a, int b) {
    return a + b;
}

double add(int a, int b) {
    return a + b;
}

The parameters must be different.

17. What is a Constructor, and when is it invoked?

Definition: A constructor is a special method used to initialize an object.

It is automatically invoked when an object is created.

Example:

class Student {
    Student() {
        System.out.println("Object created");
    }
}

Student s = new Student();

The constructor is called when new Student() executes.

18. Does a constructor have a return type?

Answer: No. A constructor does not have any return type, not even void.

Example:

class Student {
    Student() {
    }
}

19. What is a Parameterized Constructor?

Definition: A parameterized constructor accepts parameters to initialize an object with specific values.

Example:

class Student {
    String name;

    Student(String name) {
        this.name = name;
    }
}

Student s = new Student("Harshith");

20. What is a Default Constructor?

Definition: A default constructor is a constructor with no parameters.

If no constructor is written, Java provides a default no-argument constructor automatically.

Example:

class Student {
    Student() {
        System.out.println("Default constructor");
    }
}

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21. Explain the `this` keyword.

Definition:this refers to the current object.

It is commonly used to differentiate instance variables from local variables.

Example:

class Student {
    String name;

    Student(String name) {
        this.name = name;
    }
}

22. Explain the `super` keyword.

Definition:super refers to the parent class object.

It can be used to access parent class variables, methods, and constructors.

Example:

class Animal {
    String name = "Animal";
}

class Dog extends Animal {
    void display() {
        System.out.println(super.name);
    }
}

23. Why is there no multiple inheritance with classes in Java?

Answer: Java does not support multiple inheritance with classes because it can create ambiguity, known as the Diamond Problem.

Example idea:

If two parent classes have the same method, Java would not know which method the child should inherit.

Java solves this by allowing multiple inheritance through interfaces.

24. Explain the `interface` keyword.

Definition: An interface defines a set of methods that implementing classes must provide.

Example:

interface Vehicle {
    void start();
}

25. Can a class implement multiple interfaces?

Answer: Yes. A class can implement multiple interfaces.

Example:

interface A {
    void methodA();
}

interface B {
    void methodB();
}

class Test implements A, B {
    public void methodA() {}

    public void methodB() {}
}

26. What is the `enum` keyword for enumeration?

Definition: The enum keyword is used to define a fixed set of constants.

Example:

enum Day {
    MONDAY, TUESDAY, WEDNESDAY
}

27. What is the syntax for `enum`?

enum EnumName {
    CONSTANT1,
    CONSTANT2,
    CONSTANT3
}

Example:

enum Color {
    RED, GREEN, BLUE
}

28. Explain the `final` keyword for constant declaration.

Definition: The final keyword is used to make a variable constant. Its value cannot be changed.

Example:

final double PI = 3.14159;

After assigning the value, it cannot be changed.

29. Does a `List` allow duplicates?

Answer: Yes. A List allows duplicate elements.

Example:

List<String> names = new ArrayList<>();

names.add("Harshith");
names.add("Sai");
names.add("Harshith");

Duplicates are allowed.

30. What collection handles key-value pairs?

Answer: The Map collection handles key-value pairs.

Example:

Map<Integer, String> students = new HashMap<>();

students.put(1, "Harshith");
students.put(2, "Sai");

31. What is a Servlet?

Definition: A Servlet is a Java program that runs on a web server and handles client requests and generates dynamic responses.

Example: A servlet can receive login information from a user and send a response.

32. What is `jakarta.servlet`?

Definition:jakarta.servlet is the package/API containing classes and interfaces required for developing Java Servlets.

Example imports:

import jakarta.servlet.*;
import jakarta.servlet.http.*;

33. Explain the servlet lifecycle methods: `init()`, `service()`, and `destroy()`.

The servlet lifecycle has three main methods:

1. `init()`

Called once when the servlet is initialized.

2. `service()`

Called whenever a request comes to the servlet.

3. `destroy()`

Called once before the servlet is removed from memory.

Example:

public void init() {
    System.out.println("Servlet started");
}

public void destroy() {
    System.out.println("Servlet destroyed");
}

34. What is `doGet()` to serve requests?

Definition:doGet() handles HTTP GET requests.

GET is generally used to retrieve data.

Example:

protected void doGet(HttpServletRequest request,
                     HttpServletResponse response) {
}

35. What is `doPost()` to handle POST requests?

Definition:doPost() handles HTTP POST requests.

POST is commonly used to send or submit data.

Example:

protected void doPost(HttpServletRequest request,
                      HttpServletResponse response) {
}

36. What is `HttpServletRequest`?

Definition:HttpServletRequest is an object used to receive information sent by the client to a servlet.

Example:

String name = request.getParameter("name");

37. Explain `RequestDispatcher` (`include` & `forward`).

Definition:RequestDispatcher is used to transfer a request from one server resource to another.

It provides:

forward()
include()

Example:

RequestDispatcher rd =
    request.getRequestDispatcher("next.jsp");

38. What is the `forward` action?

Definition:forward() transfers the request and response completely to another resource.

Example:

rd.forward(request, response);

The browser URL does not change.

39. What is the `include` action?

Definition:include() includes the output of another resource in the current response.

Example:

rd.include(request, response);

The current servlet continues after including the other resource.

40. Explain `setAttribute()` for storing and `getAttribute()` for retrieving data.

Definition:setAttribute() stores an object, and getAttribute() retrieves it.

Example:

request.setAttribute("name", "Harshith");

Retrieving:

String name =
    (String) request.getAttribute("name");

41. What is `sendRedirect()`?

Definition:sendRedirect() tells the browser to send a new request to another URL.

Example:

response.sendRedirect("welcome.jsp");

The browser URL changes.

42. Compare `sendRedirect` vs `forward` vs `include`.

Feature	`forward()`	`include()`	`sendRedirect()`
Request	Same request	Same request	New request
URL changes	No	No	Yes
Control	Transferred	Returns back	Browser redirects
Performance	Faster	Faster	Comparatively slower

43. What is `HttpSession` to manage user sessions?

Definition:HttpSession is used to store user information across multiple requests.

Example:

HttpSession session = request.getSession();

session.setAttribute("username", "Harshith");

44. How does `request.getSession()` work?

Definition:request.getSession() returns the current session. If no session exists, it creates a new session.

Example:

HttpSession session = request.getSession();

45. What does `session.invalidate()` do?

Definition:session.invalidate() destroys the current session and removes all session attributes.

Example:

session.invalidate();

It is commonly used during logout.

Definition: A Cookie is a small piece of data stored in the user’s browser.

It is commonly used for:

Remembering users
Session tracking
Preferences

Example:

Cookie cookie = new Cookie("username", "Harshith");
response.addCookie(cookie);

47. What does the `@` symbol mean (Annotation)?

Definition: The @ symbol represents an Annotation in Java.

Annotations provide metadata or instructions to Java, the compiler, or frameworks.

Example:

@Override

Another example:

@WebServlet("/hello")

48. What is the full form of JSF / JSP?

JSF: JavaServer Faces JSP: JavaServer Pages

49. What is the `@WebServlet` annotation?

Definition:@WebServlet is used to map a Servlet to a specific URL.

Example:

@WebServlet("/hello")
public class HelloServlet extends HttpServlet {
}

When /hello is requested, this servlet handles the request.

50. Explain JSP for creating dynamic web pages.

Definition: JSP (JavaServer Pages) is a technology used to create dynamic web pages using HTML with Java-based server-side processing.

Example:

<h1>Welcome <%= request.getParameter("name") %></h1>

51. What is the JSP translation phase to a servlet program?

Definition: During the JSP translation phase, the JSP file is converted into a Servlet source code by the web container.

Process:

JSP File
   ↓
Translated into Servlet
   ↓
Compiled
   ↓
Class File Created
   ↓
Executed

Page 5

52. Name the JSP directives (`page`, `include`, `taglib`).

The three main JSP directives are:

page
include
taglib

Example:

<%@ page language="java"%>
<%@ include file="header.jsp"%>
<%@ taglib prefix="c" uri="jakarta.tags.core"%>

53. What implicit object represents the application context?

Answer: The application implicit object represents the application context.

It is of type:

ServletContext

54. Explain the four scopes in JSP.

1. Page Scope

Available only on the current JSP page.

2. Request Scope

Available during one HTTP request.

3. Session Scope

Available throughout the user’s session.

4. Application Scope

Available to all users throughout the application.

55. What is the `Throwable` implicit object for exceptions?

Answer: The JSP implicit object used to handle exceptions is exception.

Its type is:

Throwable

It is available on JSP error pages.

56. Explain `<c:if>` for conditionals in JSTL.

Definition:<c:if> is used to perform conditional operations in JSP using JSTL.

Example:

<c:if test="${age >= 18}">
    You are eligible.
</c:if>

57. Why is JSTL more advantageous than JSP scriptlets?

Answer: JSTL is preferred because it:

Makes JSP code cleaner
Reduces Java code inside HTML
Improves readability
Makes maintenance easier
Supports separation of presentation and business logic

Scriptlet:

<% if(age >= 18) { %>

JSTL:

<c:if test="${age >= 18}">

JSTL is cleaner and recommended.

58. Explain Encapsulation & Abstraction with examples in Java.

Encapsulation

Definition: Encapsulation means protecting data by keeping variables private and accessing them through methods.

class Account {
    private double balance;

    public void setBalance(double balance) {
        this.balance = balance;
    }

    public double getBalance() {
        return balance;
    }
}

Abstraction

Definition: Abstraction hides implementation details and shows only required functionality.

abstract class Vehicle {
    abstract void start();
}

59. Differentiate between `RequestDispatcher.forward`, `RequestDispatcher.include`, and `response.sendRedirect`.

Feature	`forward()`	`include()`	`sendRedirect()`
Request	Same	Same	New
URL changes	No	No	Yes
Response	Fully transferred	Included in current response	New response
Speed	Fast	Fast	Slower

60. Define Polymorphism. Discuss Method Overloading with an example.

Definition: Polymorphism means one method or object can take multiple forms.

Method Overloading occurs when methods have the same name but different parameters.

class Calculator {
    int add(int a, int b) {
        return a + b;
    }

    int add(int a, int b, int c) {
        return a + b + c;
    }
}

This is compile-time polymorphism.

61. Define Polymorphism. Discuss Method Overriding with an example.

Definition: Polymorphism allows the same method to behave differently.

Method Overriding occurs when a child class changes the implementation of a parent method.

class Animal {
    void sound() {
        System.out.println("Animal sound");
    }
}

class Dog extends Animal {
    void sound() {
        System.out.println("Bark");
    }
}

This is runtime polymorphism.

62. Compare Method Overloading vs Method Overriding.

Method Overloading	Method Overriding
Same class	Parent and child classes
Same method name	Same method name
Different parameters	Same parameters
Compile-time	Runtime
Inheritance not required	Inheritance required

63. Define Inheritance. Explain with an example.

Definition: Inheritance is an OOP concept where one class acquires the properties and methods of another class.

Example:

class Animal {
    void eat() {
        System.out.println("Eating");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println("Barking");
    }
}

Dog inherits eat() from Animal.

64. Define Interface. Explain with an example.

Definition: An interface defines a contract that implementing classes must follow.

Example:

interface Vehicle {
    void start();
}

class Car implements Vehicle {
    public void start() {
        System.out.println("Car starts");
    }
}

Page 4

65. Explain Enumerations and methods associated with enumerations.

Definition: An enumeration (enum) represents a fixed set of constants.

Example:

enum Day {
    MONDAY, TUESDAY, WEDNESDAY
}

Common methods:

`values()`

Returns all enum constants.

Day[] days = Day.values();

`valueOf()`

Converts a String into an enum constant.

Day d = Day.valueOf("MONDAY");

`ordinal()`

Returns the position of the constant.

System.out.println(Day.MONDAY.ordinal());

`name()`

Returns the name of the constant.

System.out.println(Day.MONDAY.name());

66. Explain the lifecycle and working of Servlets and JSP.

Servlet Lifecycle

Loading
↓
init()
↓
service()
↓
destroy()

init() → Called once
service() → Handles requests
destroy() → Called before removal

JSP Lifecycle

JSP Translation
↓
Compilation
↓
Class Loading
↓
jspInit()
↓
_jspService()
↓
jspDestroy()

JSP is translated internally into a Servlet.

67. Explain session management using Cookies and `HttpSession`.

Cookies

Cookies store small pieces of information in the browser.

Cookie c = new Cookie("name", "Harshith");
response.addCookie(c);

HttpSession

HttpSession stores information on the server.

HttpSession session = request.getSession();
session.setAttribute("name", "Harshith");

68. Write a complete sample Servlet program.

import java.io.IOException;
import java.io.PrintWriter;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

@WebServlet("/hello")
public class HelloServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");

        PrintWriter out = response.getWriter();

        out.println("<html>");
        out.println("<body>");
        out.println("<h1>Hello, Welcome to Servlet!</h1>");
        out.println("</body>");
        out.println("</html>");
    }
}

When the /hello URL is accessed, the servlet displays the message.

69. Define JSP and explain its lifecycle.

Definition: JSP (JavaServer Pages) is a technology used to create dynamic web pages.

JSP Lifecycle

Translation
Compilation
Class Loading
jspInit()
_jspService()
jspDestroy()

Explanation:

jspInit() → Initializes JSP once
_jspService() → Handles requests
jspDestroy() → Cleans resources

<%@ page language="java"%>

2. Include Directive

<%@ include file="header.jsp"%>

3. Taglib Directive

<%@ taglib prefix="c" uri="jakarta.tags.core"%>

Example:

<%@ page language="java"%>

<html>
<body>
    <h1>Welcome to JSP</h1>
</body>
</html>

72. Explain JSTL tags.

Definition: JSTL stands for JSP Standard Tag Library.

It provides tags for common operations without writing Java scriptlets.

Common JSTL libraries include:

Core tags
Formatting tags
Function tags
SQL tags

Example:

<c:if test="${age >= 18}">
    Eligible
</c:if>

73. State the advantages between JSP, JSTL, and Servlets.

Servlet Advantages

Handles request processing
Suitable for business logic
High control over HTTP requests

JSP Advantages

Easy to create dynamic web pages
HTML-friendly
Suitable for presentation layer

JSTL Advantages

Reduces Java code in JSP
Makes code cleaner
Easy conditional and loop operations

Best architecture:

Servlet → Business Logic
JSP → Presentation
JSTL → Dynamic Page Operations

74. Explain JSTL core tags and Expression Language (EL) with suitable examples.

JSTL Core Tags

Common tags include:

<c:if>
<c:forEach>
<c:set>
<c:choose>

Example:

<c:set var="name" value="Harshith"/>

<c:if test="${name == 'Harshith'}">
    Hello Harshith
</c:if>

Expression Language (EL)

EL is used to access variables easily.

Example:

${name}

Instead of:

<%= request.getAttribute("name") %>

75. Define constructor and differentiate between default and parameterized constructors.

Definition: A constructor initializes an object when it is created.

Default Constructor

No parameters.

Student() {
}

Parameterized Constructor

Accepts parameters.

Student(String name) {
    this.name = name;
}

Default	Parameterized
No arguments	Takes arguments
Basic initialization	Custom initialization

76. Write a note on `setAttribute` and `getAttribute` in a Servlet.

`setAttribute()`

Used to store an object.

request.setAttribute("name", "Harshith");

`getAttribute()`

Used to retrieve the stored object.

String name =
    (String) request.getAttribute("name");

These are commonly used when forwarding data from a Servlet to a JSP.

77. Explain operators in Java with examples.

1. Arithmetic Operators

+  -  *  /  %

Example:

int sum = 10 + 5;

2. Relational Operators

== != > < >= <=

Example:

10 > 5

3. Logical Operators

&& || !

Example:

age >= 18 && age <= 60

4. Assignment Operators

= += -= *= /=

5. Unary Operators

++ --

78. Briefly explain Filters and mention the `@WebFilter` annotation with an example program.

Definition: A Filter is used to intercept requests and responses before they reach a Servlet or JSP.

Common uses:

Authentication
Logging
Validation
Security

Example:

import java.io.IOException;
import jakarta.servlet.*;
import jakarta.servlet.annotation.WebFilter;

@WebFilter("/*")
public class MyFilter implements Filter {

    public void doFilter(ServletRequest request,
                         ServletResponse response,
                         FilterChain chain)
            throws IOException, ServletException {

        System.out.println("Request received");

        chain.doFilter(request, response);
    }
}

@WebFilter maps the filter to specific URLs.

79. Compare Filters vs Listeners.

Filters	Listeners
Intercept requests and responses	Listen to application events
Used for authentication	Used for session/application events
Uses `doFilter()`	Uses event methods
Can modify requests/responses	Usually monitors lifecycle events

80. Compare Cookies vs `HttpSession` for session management in Java.

Cookies	HttpSession
Stored in browser	Stored on server
Small data storage	Can store larger objects
Can be modified by user	More secure
Sent with requests	Identified using session ID

Page 3

81. Write a sample JSP program.

<%@ page language="java"%>

<html>
<head>
    <title>Sample JSP</title>
</head>

<body>
    <h1>Welcome to JSP</h1>

    <%
        String name = "Harshith";
    %>

    <p>Hello <%= name %></p>

</body>
</html>

82. Explain JSTL formatting and function libraries with an example.

Formatting Library

Used for:

Date formatting
Number formatting
Internationalization

Example:

<fmt:formatNumber value="12345.67"
                  type="currency"/>

Function Library

Provides useful string functions.

Example:

${fn:length(name)}

This returns the length of the string.

83. Write a note on Java Access Modifiers with examples.

Java has four access modifiers:

1. `private`

Accessible only within the same class.

private int age;

2. Default

Accessible within the same package.

int age;

3. `protected`

Accessible within the package and subclasses.

protected int age;

4. `public`

Accessible from anywhere.

public int age;

84. How is Exception Handling done in Servlets and JSP?

Exception handling prevents programs from crashing when errors occur.

Servlet

Use try-catch.

try {
    int a = 10 / 0;
} catch (Exception e) {
    response.getWriter().println(e.getMessage());
}

JSP

JSP can use an error page.

Main JSP:

<%@ page errorPage="error.jsp"%>

error.jsp:

<%@ page isErrorPage="true"%>

Error: ${exception.message}

85. Summarize the differences between `forward`, `include`, and `sendRedirect`.

`forward()`

Transfers the complete request to another resource.

rd.forward(request, response);

Same request
URL does not change
Current resource stops processing

`include()`

Includes another resource’s output.

rd.include(request, response);

Same request
URL does not change
Current resource continues processing

`sendRedirect()`

Tells the browser to make a new request.

response.sendRedirect("welcome.jsp");

New request
URL changes
Can redirect to another application or URL

Final Comparison

Feature	Forward	Include	sendRedirect
Request	Same	Same	New
URL Changes	No	No	Yes
Current Processing	Stops	Continues	New request
Speed	Faster	Faster	Comparatively slower

Adv-Java Unit 1 & 2: Extra Questions

1. Which of the following is OOPs?Copy Anchor Link

2. Explain the class keyword.Copy Anchor Link

3. Is String a primitive data type?Copy Anchor Link

4. What is the size of int in bytes?Copy Anchor Link

5. How is char used to store a single character?Copy Anchor Link

6. Explain the new keyword to create an object.Copy Anchor Link

7. Explain the statement Student s = new Student() to create an object.Copy Anchor Link

8. Define Abstraction (showing only required details).Copy Anchor Link

9. Define Encapsulation.Copy Anchor Link

10. What is the protected access modifier?Copy Anchor Link

11. What is the extends keyword in Inheritance?Copy Anchor Link

12. What is the implements keyword?Copy Anchor Link

13. Define Polymorphism.Copy Anchor Link

14. Explain Method Overloading (compile-time polymorphism).Copy Anchor Link

15. Explain Method Overriding (runtime polymorphism).Copy Anchor Link

16. Can methods be overloaded by changing the return type?Copy Anchor Link

17. What is a Constructor, and when is it invoked?Copy Anchor Link

18. Does a constructor have a return type?Copy Anchor Link

19. What is a Parameterized Constructor?Copy Anchor Link

20. What is a Default Constructor?Copy Anchor Link

Page 2Copy Anchor Link

21. Explain the this keyword.Copy Anchor Link

22. Explain the super keyword.Copy Anchor Link

23. Why is there no multiple inheritance with classes in Java?Copy Anchor Link

24. Explain the interface keyword.Copy Anchor Link

25. Can a class implement multiple interfaces?Copy Anchor Link

26. What is the enum keyword for enumeration?Copy Anchor Link

27. What is the syntax for enum?Copy Anchor Link

28. Explain the final keyword for constant declaration.Copy Anchor Link

29. Does a List allow duplicates?Copy Anchor Link

30. What collection handles key-value pairs?Copy Anchor Link

31. What is a Servlet?Copy Anchor Link

32. What is jakarta.servlet?Copy Anchor Link

33. Explain the servlet lifecycle methods: init(), service(), and destroy().Copy Anchor Link

1. init()Copy Anchor Link

2. service()Copy Anchor Link

3. destroy()Copy Anchor Link

34. What is doGet() to serve requests?Copy Anchor Link

35. What is doPost() to handle POST requests?Copy Anchor Link

36. What is HttpServletRequest?Copy Anchor Link

37. Explain RequestDispatcher (include & forward).Copy Anchor Link

38. What is the forward action?Copy Anchor Link

39. What is the include action?Copy Anchor Link

40. Explain setAttribute() for storing and getAttribute() for retrieving data.Copy Anchor Link

41. What is sendRedirect()?Copy Anchor Link

42. Compare sendRedirect vs forward vs include.Copy Anchor Link

43. What is HttpSession to manage user sessions?Copy Anchor Link

44. How does request.getSession() work?Copy Anchor Link

45. What does session.invalidate() do?Copy Anchor Link

46. What is a Cookie (small piece of data)?Copy Anchor Link

47. What does the @ symbol mean (Annotation)?Copy Anchor Link

48. What is the full form of JSF / JSP?Copy Anchor Link

49. What is the @WebServlet annotation?Copy Anchor Link

50. Explain JSP for creating dynamic web pages.Copy Anchor Link

51. What is the JSP translation phase to a servlet program?Copy Anchor Link

Page 5Copy Anchor Link

52. Name the JSP directives (page, include, taglib).Copy Anchor Link

53. What implicit object represents the application context?Copy Anchor Link

54. Explain the four scopes in JSP.Copy Anchor Link

1. Page ScopeCopy Anchor Link

2. Request ScopeCopy Anchor Link

3. Session ScopeCopy Anchor Link

4. Application ScopeCopy Anchor Link

55. What is the Throwable implicit object for exceptions?Copy Anchor Link

56. Explain <c:if> for conditionals in JSTL.Copy Anchor Link

57. Why is JSTL more advantageous than JSP scriptlets?Copy Anchor Link

58. Explain Encapsulation & Abstraction with examples in Java.Copy Anchor Link

EncapsulationCopy Anchor Link

AbstractionCopy Anchor Link

59. Differentiate between RequestDispatcher.forward, RequestDispatcher.include, and response.sendRedirect.Copy Anchor Link

60. Define Polymorphism. Discuss Method Overloading with an example.Copy Anchor Link

61. Define Polymorphism. Discuss Method Overriding with an example.Copy Anchor Link

62. Compare Method Overloading vs Method Overriding.Copy Anchor Link

63. Define Inheritance. Explain with an example.Copy Anchor Link

64. Define Interface. Explain with an example.Copy Anchor Link

Page 4Copy Anchor Link

65. Explain Enumerations and methods associated with enumerations.Copy Anchor Link

values()Copy Anchor Link

valueOf()Copy Anchor Link

1. Which of the following is OOPs?

2. Explain the `class` keyword.

3. Is `String` a primitive data type?

4. What is the size of `int` in bytes?

5. How is `char` used to store a single character?

6. Explain the `new` keyword to create an object.

7. Explain the statement `Student s = new Student()` to create an object.

8. Define Abstraction (showing only required details).

9. Define Encapsulation.

10. What is the `protected` access modifier?

11. What is the `extends` keyword in Inheritance?

12. What is the `implements` keyword?

13. Define Polymorphism.

14. Explain Method Overloading (compile-time polymorphism).

15. Explain Method Overriding (runtime polymorphism).

16. Can methods be overloaded by changing the return type?

17. What is a Constructor, and when is it invoked?

18. Does a constructor have a return type?

19. What is a Parameterized Constructor?

20. What is a Default Constructor?

Page 2

21. Explain the `this` keyword.

22. Explain the `super` keyword.

23. Why is there no multiple inheritance with classes in Java?

24. Explain the `interface` keyword.

25. Can a class implement multiple interfaces?

26. What is the `enum` keyword for enumeration?

27. What is the syntax for `enum`?

28. Explain the `final` keyword for constant declaration.

29. Does a `List` allow duplicates?

30. What collection handles key-value pairs?

31. What is a Servlet?

32. What is `jakarta.servlet`?

33. Explain the servlet lifecycle methods: `init()`, `service()`, and `destroy()`.

1. `init()`

2. `service()`

3. `destroy()`

34. What is `doGet()` to serve requests?

35. What is `doPost()` to handle POST requests?

36. What is `HttpServletRequest`?

37. Explain `RequestDispatcher` (`include` & `forward`).

38. What is the `forward` action?

39. What is the `include` action?

40. Explain `setAttribute()` for storing and `getAttribute()` for retrieving data.

41. What is `sendRedirect()`?

42. Compare `sendRedirect` vs `forward` vs `include`.

43. What is `HttpSession` to manage user sessions?

44. How does `request.getSession()` work?

45. What does `session.invalidate()` do?

46. What is a Cookie (small piece of data)?

47. What does the `@` symbol mean (Annotation)?

48. What is the full form of JSF / JSP?

49. What is the `@WebServlet` annotation?

50. Explain JSP for creating dynamic web pages.

51. What is the JSP translation phase to a servlet program?

Page 5

52. Name the JSP directives (`page`, `include`, `taglib`).

53. What implicit object represents the application context?

54. Explain the four scopes in JSP.

1. Page Scope

2. Request Scope

3. Session Scope

4. Application Scope

55. What is the `Throwable` implicit object for exceptions?

56. Explain `<c:if>` for conditionals in JSTL.

57. Why is JSTL more advantageous than JSP scriptlets?

58. Explain Encapsulation & Abstraction with examples in Java.

Encapsulation

Abstraction

59. Differentiate between `RequestDispatcher.forward`, `RequestDispatcher.include`, and `response.sendRedirect`.

60. Define Polymorphism. Discuss Method Overloading with an example.

61. Define Polymorphism. Discuss Method Overriding with an example.

62. Compare Method Overloading vs Method Overriding.

63. Define Inheritance. Explain with an example.

64. Define Interface. Explain with an example.

Page 4

65. Explain Enumerations and methods associated with enumerations.

`values()`

`valueOf()`

`ordinal()`