SECTION I: MULTIPLE CHOICE QUESTIONS (1 Mark Each)Copy Anchor Link

1. Which JDBC object is primarily used to establish a connection with a database?

1. Statement | b) DriverManager | c) ResultSet | d) SQLException

Answer: b) DriverManager -> Explanation: DriverManager is the class used to establish connections. It manages JDBC drivers and provides getConnection() method to create a Connection object.

2. Which JDBC driver type converts JDBC calls into calls to the database-specific native API?

1. Type 1 | b) Type 2 | c) Type 3 | d) Type 4

Answer: b) Type 2 -> Explanation: Type 2 (Native API Driver) converts JDBC calls into database-specific native API calls. It uses native libraries and is faster than Type 1 but platform-dependent.

3. Which package contains the core JDBC interfaces and classes?

1. java.io | b) java.sql | c) javax.swing | d) org.springframework

Answer: b) java.sql -> Explanation: The java.sql package contains core JDBC classes and interfaces such as Connection, Statement, PreparedStatement, CallableStatement, and ResultSet.

4. Which method is used to execute a SQL SELECT statement and return a ResultSet?

1. executeUpdate() | b) executeQuery() | c) execute() | d) runQuery()

Answer: b) executeQuery() -> Explanation: executeQuery() is used for SELECT statements. It returns a ResultSet object containing the query results.

5. Which JDBC object represents the tabular data returned by a SELECT query?

1. Connection | b) Statement | c) ResultSet | d) DatabaseMetaData

Answer: c) ResultSet -> Explanation: ResultSet stores the results of a SQL query in tabular form. It maintains a cursor pointing to the current row and provides methods like next(), getString(), getInt().

6. Which interface is used to control commit and rollback of a JDBC transaction?

1. ResultSet | b) Connection | c) Driver | d) Statement

Answer: b) Connection -> Explanation: The Connection interface provides commit(), rollback(), and setAutoCommit() methods to control transactions.

7. Which Swing component is commonly used to accept a single line of text?

1. JLabel | b) JTextField | c) JTextArea | d) JPanel

Answer: b) JTextField -> Explanation: JTextField accepts a single line of text input. JTextArea is for multi-line text; JLabel displays non-editable text.

8. Which Swing component is used as a top-level container for a desktop application?

1. JButton | b) JFrame | c) JLabel | d) JCheckBox

Answer: b) JFrame -> Explanation: JFrame is the top-level container (main window) in Swing. It holds other components and provides the window frame with title bar, minimize, maximize, and close buttons.

9. Which Spring feature allows an object to receive its dependencies from outside rather than creating them itself?

1. Inheritance | b) Dependency Injection | c) Encapsulation | d) Overloading

Answer: b) Dependency Injection -> Explanation: Dependency Injection (DI) is the process of providing dependencies to an object from outside, typically by the Spring container. It promotes loose coupling.

10. Which injection technique supplies dependencies through a class constructor?

1. Field injection | b) Constructor injection | c) Setter injection | d) Method overriding

Answer: b) Constructor injection -> Explanation: Constructor Injection provides dependencies through the class constructor. It ensures mandatory dependencies are provided at object creation and supports immutability.

11. Which Spring MVC annotation maps a web request to a controller method?

1. @Bean | b) @Autowired | c) @RequestMapping | d) @Component

Answer: c) @RequestMapping -> Explanation: @RequestMapping maps URL requests to controller methods. It can specify the path, HTTP method, parameters, and headers.

12. Which Spring feature defines how long a bean instance exists in the container?

1. Bean scope | b) Bean validation | c) Request mapping | d) JDBC driver

Answer: a) Bean scope -> Explanation: Bean scope defines the lifecycle and visibility of a bean instance. Common scopes: singleton (default), prototype, request, session, application.

13. Which class is commonly used to obtain a JDBC database connection?

1. DriverManager | b) ResultSet | c) SQLException | d) JFrame

Answer: a) DriverManager -> Explanation: DriverManager.getConnection(url, user, password) is the standard way to obtain a database connection in JDBC.

14. Which JDBC driver is known as the pure Java driver and directly communicates with the database server?

1. Type 1 | b) Type 2 | c) Type 3 | d) Type 4

Answer: d) Type 4 -> Explanation: Type 4 (Thin Driver) is a pure Java driver that communicates directly with the database server. It is the fastest, most portable, and most commonly used.

15. Which JDBC interface represents a SQL statement sent to the database?

1. Connection | b) Statement | c) ResultSet | d) DatabaseMetaData

Answer: b) Statement -> Explanation: The Statement interface represents a SQL statement sent to the database. It is created via con.createStatement() and executed via executeQuery() or executeUpdate().

16. Which method is generally used to execute INSERT, UPDATE or DELETE statements?

1. executeQuery() | b) executeUpdate() | c) executeSelect() | d) getUpdate()

Answer: b) executeUpdate() -> Explanation: executeUpdate() is used for INSERT, UPDATE, and DELETE statements. It returns an int representing the number of affected rows.

17. Which JDBC object provides information about columns and other properties of query results?

1. ResultSetMetaData | b) DriverManager | c) Statement | d) Connection

Answer: a) ResultSetMetaData -> Explanation: ResultSetMetaData provides information about columns in a ResultSet: column names, data types, column count, etc.

18. Which method makes the changes made in a transaction permanent?

1. rollback() | b) commit() | c) close() | d) execute()

Answer: b) commit() -> Explanation: commit() saves all changes made in the current transaction permanently to the database.

19. Which Swing component displays a command button that can generate an action event?

1. JButton | b) JTextField | c) JLabel | d) JPanel

Answer: a) JButton -> Explanation: JButton displays a clickable button. When clicked, it generates an ActionEvent that can be handled by an ActionListener.

20. Which Swing container can hold other Swing components and is commonly used to organize a GUI?

1. JPanel | b) JTextField | c) JButton | d) JLabel

Answer: a) JPanel -> Explanation: JPanel is a lightweight container used to group and organize other components. It can have its own layout manager.

21. Which Spring principle states that the framework controls object creation and dependency management?

1. Inversion of Control | b) Method Overloading | c) Encapsulation | d) Polymorphism

Answer: a) Inversion of Control -> Explanation: Inversion of Control (IoC) means object creation and dependency management are transferred from the programmer to the Spring container.

22. Which annotation is commonly used to inject a dependency into a Spring bean?

1. @Autowired | b) @RequestMapping | c) @Override | d) @Table

Answer: a) @Autowired -> Explanation: @Autowired is used for automatic dependency injection. It can be applied to constructors, setters, or fields.

23. Which Spring MVC facility provides tags such as form, input and errors for HTML forms?

1. JDBC API | b) Spring MVC Form Tag Library | c) JSTL SQL tags | d) Swing Controls

Answer: b) Spring MVC Form Tag Library -> Explanation: The Spring MVC Form Tag Library provides JSP tags like <form:form>, <form:input>, <form:errors> for data binding and validation.

24. Which feature of Spring is used to check form data against validation rules?

1. Spring Validation | b) Bean Scope | c) JDBC Metadata | d) Swing Layout

Answer: a) Spring Validation -> Explanation: Spring Validation uses annotations like @NotNull, @Email, @Size, @Min, @Max to validate form data.

25. What is the main purpose of the JDBC API?

1. To create graphical interfaces | b) To connect Java applications with databases | c) To compile Java programs | d) To manage Swing layouts

Answer: b) To connect Java applications with databases -> Explanation: JDBC (Java Database Connectivity) is a Java API that allows Java applications to connect to databases, execute SQL queries, and process results.

26. Which JDBC driver uses a middleware server between the Java application and database?

1. Type 1 | b) Type 2 | c) Type 3 | d) Type 4

Answer: c) Type 3 -> Explanation: Type 3 (Network Protocol Driver) uses a middleware server between the Java application and the database. It is database-independent but requires an additional server.

27. Which object contains the database session established by a JDBC application?

1. Connection | b) ResultSet | c) Statement | d) Metadata

Answer: a) Connection -> Explanation: The Connection object represents an active session with the database. It is used to create statements and manage transactions.

28. Which method can execute a SQL statement that may return either a ResultSet or an update count?

1. execute() | b) executeQuery() | c) executeUpdate() | d) run()

Answer: a) execute() -> Explanation: execute() is used when the query type is unknown. It returns true if the result is a ResultSet, false if it is an update count.

29. Which metadata interface provides information about a database, such as supported features and tables?

1. ResultSetMetaData | b) DatabaseMetaData | c) ConnectionMetaData | d) DriverMetaData

Answer: b) DatabaseMetaData -> Explanation: DatabaseMetaData provides information about the database and DBMS: product name, version, supported features, tables, etc.

30. What is the default JDBC transaction mode in which each statement is committed automatically?

1. Manual commit | b) Auto-commit | c) Rollback mode | d) Batch mode

Answer: b) Auto-commit -> Explanation: By default, JDBC uses auto-commit mode, where each SQL statement is treated as a transaction and committed automatically.

31. Which Swing component is used to display non-editable text or an image?

1. JLabel | b) JButton | c) JTextField | d) JComboBox

Answer: a) JLabel -> Explanation: JLabel displays non-editable text or an image. It is commonly used for labels and descriptions.

32. Which Swing component allows the user to select one option from a drop-down list?

1. JList | b) JComboBox | c) JPanel | d) JFrame

Answer: b) JComboBox -> Explanation: JComboBox provides a drop-down list from which the user can select one option.

33. Which Spring mechanism creates and manages objects called beans?

1. Spring IoC container | b) JDBC DriverManager | c) Swing Event Queue | d) JSP Engine

Answer: a) Spring IoC container -> Explanation: The Spring IoC container creates and manages objects (beans), injects dependencies, and manages their lifecycle.

34. Which injection method supplies a dependency by assigning it directly to a field?

1. Constructor injection | b) Setter injection | c) Field injection | d) Interface injection

Answer: c) Field injection -> Explanation: Field Injection uses @Autowired directly on fields. It requires less code but is harder to test than constructor injection.

35. Which annotation can be used at the controller level or method level to map web requests in Spring MVC?

1. @RequestMapping | b) @Bean | c) @Scope | d) @PostConstruct

Answer: a) @RequestMapping -> Explanation: @RequestMapping can be applied at both class level (base path) and method level (specific endpoint) to map web requests.

36. Which Spring MVC feature is used to report validation errors in form data?

1. Form validation and BindingResult | b) ResultSet | c) JFrame | d) DriverManager

Answer: a) Form validation and BindingResult -> Explanation: @Valid triggers validation, and BindingResult captures validation errors. Errors are displayed using <form:errors>.

37. Which JDBC interface is responsible for representing a connection to a specific database?

1. Connection | b) Driver | c) Statement | d) ResultSet

Answer: a) Connection -> Explanation: The Connection interface represents a connection (session) to a specific database. It is obtained via DriverManager.getConnection().

38. Which JDBC driver type translates JDBC calls into a database-independent network protocol used by middleware?

1. Type 1 | b) Type 2 | c) Type 3 | d) Type 4

Answer: c) Type 3 -> Explanation: Type 3 (Network Protocol Driver) translates JDBC calls into a database-independent network protocol used by a middleware server.

39. Which package provides Swing components such as JFrame and JButton?

1. java.sql | b) javax.swing | c) java.net | d) org.springframework

Answer: b) javax.swing -> Explanation: The javax.swing package provides Swing components like JFrame, JButton, JLabel, JTextField, etc.

40. Which JDBC method is used to release a Connection resource?

1. release() | b) dispose() | c) close() | d) disconnect()

Answer: c) close() -> Explanation: close() releases the Connection resource and returns it to the pool or closes it. It should be called in a finally block or try-with-resources.

41. Which object is used to retrieve the values of columns from a ResultSet?

1. ResultSet | b) Connection | c) DriverManager | d) Statement

Answer: a) ResultSet -> Explanation: ResultSet provides methods like getString(), getInt(), getDate() to retrieve column values from the current row.

42. What is the purpose of rollback() in JDBC?

1. To permanently save changes | b) To undo the current transaction changes | c) To close the database | d) To create a statement

Answer: b) To undo the current transaction changes -> Explanation: rollback() undoes all changes made in the current transaction, restoring the database to its previous state.

43. Which Swing component is suitable for entering multi-line text?

1. JTextArea | b) JTextField | c) JLabel | d) JButton

Answer: a) JTextArea -> Explanation: JTextArea allows multi-line text input. JTextField is for single-line input.

44. Which component is generally used to arrange other components in a Swing application?

1. JPanel | b) JTextField | c) JButton | d) JLabel

Answer: a) JPanel -> Explanation: JPanel is a container used to group and arrange other components. It can have its own layout manager.

45. Which Spring concept enables loose coupling between classes?

1. Dependency Injection | b) Inheritance | c) Method Overloading | d) Data Hiding

Answer: a) Dependency Injection -> Explanation: Dependency Injection enables loose coupling by providing dependencies from outside rather than creating them internally.

46. Which annotation is commonly used to declare a class as a Spring-managed component?

1. @Component | b) @RequestMapping | c) @ResultSet | d) @Swing

Answer: a) @Component -> Explanation: @Component is a general-purpose stereotype annotation that marks a class as a Spring-managed bean.

47. Which Spring MVC annotation can map a controller method specifically to an HTTP GET request?

1. @GetMapping | b) @Bean | c) @Scope | d) @Autowired

Answer: a) @GetMapping -> Explanation: @GetMapping is a specialized annotation for mapping HTTP GET requests to controller methods. It is shorthand for @RequestMapping(method = RequestMethod.GET).

48. Which bean scope creates one bean instance for each HTTP request in a web-aware Spring application?

1. singleton | b) prototype | c) request | d) session

Answer: c) request -> Explanation: The request scope creates a new bean instance for each HTTP request. It is only valid in a web-aware Spring ApplicationContext.

49. Which JDBC interface is used for executing precompiled SQL statements with parameters?

1. Statement | b) PreparedStatement | c) CallableStatement | d) ResultSet

Answer: b) PreparedStatement -> Explanation: PreparedStatement is a precompiled SQL statement that can be executed multiple times with different parameters. It prevents SQL injection.

50. Which interface allows execution of stored procedures in JDBC?

1. CallableStatement | b) PreparedStatement | c) Connection | d) Driver

Answer: a) CallableStatement -> Explanation: CallableStatement is used to execute stored procedures. It is created via con.prepareCall("{call procedureName()}").

51. What type of JDBC driver is the Native-protocol all-Java driver?

1. Type 1 | b) Type 2 | c) Type 3 | d) Type 4

Answer: d) Type 4 -> Explanation: Type 4 (Thin Driver) is the Native-protocol all-Java driver. It communicates directly with the database using the database’s native protocol.

52. Which method is used to register a JDBC driver manually in older applications?

1. Class.forName() | b) DriverManager.register() | c) Driver.load() | d) System.load()

Answer: a) Class.forName() -> Explanation: Class.forName("com.mysql.cj.jdbc.Driver") loads and registers the JDBC driver class. Modern JDBC 4.0+ auto-registers drivers.

53. Which exception is thrown by JDBC methods when a database access error occurs?

1. IOException | b) SQLException | c) ClassNotFoundException | d) RemoteException

Answer: b) SQLException -> Explanation: SQLException is thrown when a database access error occurs. It provides getMessage(), getErrorCode(), and getSQLState() methods.

54. Which method of Statement interface enables batch updates?

1. addBatch() | b) executeBatch() | c) Both a and b | d) updateBatch()

Answer: c) Both a and b -> Explanation: addBatch() adds statements to the batch, and executeBatch() executes all statements in the batch. Both are needed for batch processing.

55. Which JDBC ResultSet type allows scrolling forward and backward but is not sensitive to changes made by others?

1. TYPE_FORWARD_ONLY | b) TYPE_SCROLL_INSENSITIVE | c) TYPE_SCROLL_SENSITIVE | d) CONCUR_READ_ONLY

Answer: b) TYPE_SCROLL_INSENSITIVE -> Explanation: TYPE_SCROLL_INSENSITIVE allows scrolling forward and backward but is not sensitive to changes made by others. TYPE_SCROLL_SENSITIVE reflects changes.

56. Which Swing layout places components in a single horizontal or vertical row?

1. FlowLayout | b) BoxLayout | c) GridLayout | d) CardLayout

Answer: b) BoxLayout -> Explanation: BoxLayout arranges components in a single row or column (horizontal or vertical). FlowLayout wraps components; GridLayout uses a grid.

57. Which method adds a component to a container in Java Swing?

1. insert() | b) add() | c) put() | d) attach()

Answer: b) add() -> Explanation: add(Component) adds a component to a container. It is the standard method for building Swing GUIs.

58. Which listener interface handles mouse clicks and movements in Swing?

1. ActionListener | b) MouseListener | c) WindowListener | d) KeyListener

Answer: b) MouseListener -> Explanation: MouseListener handles mouse events: mouseClicked(), mousePressed(), mouseReleased(), mouseEntered(), mouseExited().

59. Which class represents a single-selection check box menu item in Swing?

1. JCheckBoxMenuItem | b) JMenu | c) JMenuItem | d) JPopupMenu

Answer: a) JCheckBoxMenuItem -> Explanation: JCheckBoxMenuItem is a menu item with a check box. It can be selected/deselected and is used in menus.

60. Which Swing component is used to show a progress bar indicating task status?

1. JSlider | b) JProgressBar | c) JScrollBar | d) JSpinner

Answer: b) JProgressBar -> Explanation: JProgressBar displays progress of a task. It can be determinate (shows percentage) or indeterminate (animated).

61. Which method packs the components within a window to their preferred sizes?

1. resize() | b) pack() | c) fit() | d) validate()

Answer: b) pack() -> Explanation: pack() sizes the window to fit the preferred sizes and layouts of its components. It is called before setVisible(true).

62. Which Swing component allows tabular presentation of data with rows and columns?

1. JList | b) JTable | c) JTree | d) JComboBox

Answer: b) JTable -> Explanation: JTable displays data in a tabular format with rows and columns. It uses a TableModel to manage data.

63. Which package contains standard Swing event classes?

1. java.awt.event | b) javax.swing.event | c) java.sql | d) java.net

Answer: b) javax.swing.event -> Explanation: The javax.swing.event package contains Swing-specific event classes like ListSelectionEvent, TreeSelectionEvent, etc. java.awt.event contains AWT events.

64. Which Spring annotation is specialized for defining service layer components?

1. @Repository | b) @Service | c) @Controller | d) @Component

Answer: b) @Service -> Explanation: @Service is a specialized annotation for service-layer components. It is a stereotype annotation that marks a class as a Spring bean.

65. Which Spring annotation marks a data access persistence component?

1. @Repository | b) @Service | c) @Configuration | d) @Bean

Answer: a) @Repository -> Explanation: @Repository marks a data access component (DAO). It also translates database exceptions into Spring’s DataAccessException hierarchy.

66. Which annotation configures a class to act as a Spring configuration source?

1. @Configuration | b) @Bean | c) @Autowired | d) @Module

Answer: a) @Configuration -> Explanation: @Configuration marks a class as a source of bean definitions. Methods annotated with @Bean in this class define Spring beans.

67. What is the default bean scope in Spring framework?

1. prototype | b) singleton | c) request | d) session

Answer: b) singleton -> Explanation: Singleton is the default bean scope. Only one instance of the bean is created per Spring container.

68. Which Spring module supports Aspect-Oriented Programming?

1. Spring JDBC | b) Spring AOP | c) Spring MVC | d) Spring ORM

Answer: b) Spring AOP -> Explanation: Spring AOP supports Aspect-Oriented Programming, allowing separation of cross-cutting concerns like logging, security, and transactions.

69. Which annotation maps HTTP POST requests specifically in Spring MVC?

1. @GetMapping | b) @PostMapping | c) @PutMapping | d) @RequestMapping

Answer: b) @PostMapping -> Explanation: @PostMapping is a specialized annotation for mapping HTTP POST requests to controller methods. It is shorthand for @RequestMapping(method = RequestMethod.POST).

70. Which class or interface binds form data and handles validation results in Spring MVC?

1. BindingResult | b) ModelMap | c) HttpSession | d) HttpServletRequest

Answer: a) BindingResult -> Explanation: BindingResult holds the results of data binding and validation. It is used with @Valid to check for errors in form data.

71. Which Spring annotation extracts path variables from URI templates?

1. @RequestParam | b) @PathVariable | c) @RequestBody | d) @ModelAttribute

Answer: b) @PathVariable -> Explanation: @PathVariable extracts values from URI template variables. Example: /student/{id} with @PathVariable int id.

72. Which JDBC method turns off auto-commit mode?

1. setAutoCommit(false) | b) commit(false) | c) disableAutoCommit() | d) setManualCommit(true)

Answer: a) setAutoCommit(false) -> Explanation: con.setAutoCommit(false) disables auto-commit mode, allowing manual transaction control via commit() and rollback().

73. Which database metadata method checks if the database is read-only?

1. isReadOnly() | b) checkReadOnly() | c) getReadOnly() | d) readOnlyStatus()

Answer: a) isReadOnly() -> Explanation: DatabaseMetaData.isReadOnly() returns true if the database is in read-only mode.

74. Which method returns the number of columns in a ResultSet object?

1. getColumnCount() | b) getColumns() | c) countColumns() | d) size()

Answer: a) getColumnCount() -> Explanation: ResultSetMetaData.getColumnCount() returns the number of columns in the ResultSet.

75. Which interface represents a database connection pool configuration in enterprise frameworks?

1. DataSource | b) ConnectionPool | c) DBManager | d) SessionFactory

Answer: a) DataSource -> Explanation: javax.sql.DataSource represents a connection pool configuration. It is preferred over DriverManager for enterprise applications.

76. Which Swing component is used to present multiple tabs for switching panels?

1. JTabbedPane | b) JSplitPane | c) JScrollPane | d) JDesktopPane

Answer: a) JTabbedPane -> Explanation: JTabbedPane presents multiple tabs, each containing a panel. Users can switch between tabs to view different content.

77. Which layout manager flips through multiple component cards like a deck of cards?

1. CardLayout | b) FlowLayout | c) GridBagLayout | d) SpringLayout

Answer: a) CardLayout -> Explanation: CardLayout arranges components as stacked cards, showing only one at a time. It is used for wizards and tab-like interfaces.

78. Which method registers an action listener with a button?

1. addActionListener() | b) registerListener() | c) setActionListener() | d) attachListener()

Answer: a) addActionListener() -> Explanation: button.addActionListener(listener) registers an ActionListener to handle button clicks.

79. Which component provides a popup menu when right-clicked?

1. JPopupMenu | b) JMenu | c) JMenuBar | d) JMenuItem

Answer: a) JPopupMenu -> Explanation: JPopupMenu is a floating menu that appears when the user right-clicks. It contains JMenuItem components.

80. Which class is used to handle multiple text lines with scrolling support in Swing?

1. JTextField | b) JTextArea | c) JLabel | d) JPasswordBox

Answer: b) JTextArea -> Explanation: JTextArea handles multiple lines of text. When wrapped in a JScrollPane, it provides scrolling support.

81. Which interface listens for value changes in lists or tables in Swing?

1. ListSelectionListener | b) ActionListener | c) ItemListener | d) ChangeListener

Answer: a) ListSelectionListener -> Explanation: ListSelectionListener listens for selection changes in JList and JTable components.

82. Which Spring annotation is a general-purpose stereotype for any Spring-managed bean?

1. @Component | b) @Bean | c) @Service | d) @Inject

Answer: a) @Component -> Explanation: @Component is the general-purpose stereotype annotation. @Service, @Repository, and @Controller are specializations of @Component.

83. Which annotation is used to inject values from properties files into Spring beans?

1. @Value | b) @Inject | c) @Autowired | d) @Property

Answer: a) @Value -> Explanation: @Value("${property.name}") injects values from properties files into Spring bean fields.

84. Which container interface represents the advanced Spring IoC container with internationalization support?

1. ApplicationContext | b) BeanFactory | c) WebApplicationContext | d) ContainerContext

Answer: a) ApplicationContext -> Explanation: ApplicationContext is the advanced IoC container. It extends BeanFactory and adds support for internationalization, event propagation, and annotation-based configuration.

85. Which method initializes a bean lifecycle callback explicitly in Spring?

1. @PostConstruct | b) @PreDestroy | c) @Init | d) @Start

Answer: a) @PostConstruct -> Explanation: @PostConstruct marks a method to be executed after bean initialization. It is used for initialization logic.

86. Which method cleans up a bean during destruction in Spring?

1. @PreDestroy | b) @PostConstruct | c) @Destroy | d) @Clean

Answer: a) @PreDestroy -> Explanation: @PreDestroy marks a method to be executed before bean destruction. It is used for cleanup logic.

87. Which Spring annotation binds request body data directly to a method parameter object?

1. @RequestBody | b) @ResponseBody | c) @RequestParam | d) @PathVariable

Answer: a) @RequestBody -> Explanation: @RequestBody binds the HTTP request body (e.g., JSON) directly to a method parameter object.

88. Which annotation serializes controller method return values directly to JSON/XML responses?

1. @ResponseBody | b) @RequestBody | c) @JsonView | d) @RestResponse

Answer: a) @ResponseBody -> Explanation: @ResponseBody serializes the return value of a controller method directly to the HTTP response body (JSON/XML).

89. Which servlet method is called once when the servlet is first loaded?

1. init() | b) service() | c) destroy() | d) doGet()

Answer: a) init() -> Explanation: init() is called once when the servlet is first loaded. It is used for initialization logic.

90. Which interface handles client requests and responses in Java Servlets?

1. ServletRequest / ServletResponse | b) HttpServlet / HttpSession | c) Connection / Statement | d) Filter / Chain

Answer: a) ServletRequest / ServletResponse -> Explanation: ServletRequest and ServletResponse are the core interfaces for handling client requests and responses in servlets.

91. Which mechanism maintains state across multiple HTTP requests in J2EE?

1. Session tracking | b) JDBC Commit | c) Dependency Injection | d) Event Handling

Answer: a) Session tracking -> Explanation: Session tracking maintains state across multiple HTTP requests. Techniques include cookies, HttpSession, URL rewriting, and hidden form fields.

92. Which EJB type handles business logic without maintaining client state across calls?

1. Stateless Session Bean | b) Stateful Session Bean | c) Message-Driven Bean | d) Entity Bean

Answer: a) Stateless Session Bean -> Explanation: Stateless Session Beans handle business logic without maintaining client state across method calls. They are pooled and reusable.

93. Which EJB type maintains conversational state for a specific client?

1. Stateful Session Bean | b) Stateless Session Bean | c) Singleton Bean | d) Entity Bean

Answer: a) Stateful Session Bean -> Explanation: Stateful Session Beans maintain conversational state for a specific client across multiple method calls.

94. Which file acts as the primary deployment descriptor for a traditional Java web application?

1. web.xml | b) spring.xml | c) pom.xml | d) bean.xml

Answer: a) web.xml -> Explanation: web.xml is the primary deployment descriptor for a traditional Java web application. It defines servlets, filters, listeners, and URL mappings.

95. Which Java technology combines HTML and embedded Java code for server-side rendering?

1. JSP (JavaServer Pages) | b) JDBC | c) Swing | d) EJB

Answer: a) JSP (JavaServer Pages) -> Explanation: JSP combines HTML with embedded Java code for server-side rendering. JSP pages are compiled into servlets.

96. Which architectural pattern separates data, user interface, and control logic in web and desktop applications?

1. MVC (Model-View-Controller) | b) Singleton | c) Factory | d) Observer

Answer: a) MVC (Model-View-Controller) -> Explanation: MVC separates data (Model), user interface (View), and control logic (Controller). It is used in both web and desktop applications.

SECTION II: SHORT ANSWER QUESTIONS (3 Marks Each)Copy Anchor Link

1. Explain the JDBC process from loading/registering a driver to executing a SQL query and processing the ResultSet.

Answer:

The JDBC process consists of five steps:

Step 1: Load/Register Driver

Class.forName("com.mysql.cj.jdbc.Driver");

Loads the JDBC driver class into memory.

Step 2: Establish Connection

Connection con = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/test", "root", "root");

Step 3: Create Statement and Execute Query

Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM student");

Step 4: Process ResultSet

while (rs.next()) {
    System.out.println(rs.getString("name"));
}

Step 5: Close Resources

rs.close();
stmt.close();
con.close();

Complete Example:

import java.sql.*;

public class JdbcExample {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection con = DriverManager.getConnection(
            "jdbc:mysql://localhost:3306/test", "root", "root");
        Statement stmt = con.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT * FROM student");
        while (rs.next()) {
            System.out.println(rs.getString("name"));
        }
        con.close();
    }
}

2. Explain the concept of Dependency Injection in Spring. Differentiate between constructor injection and setter injection with suitable examples.

Answer:

Dependency Injection (DI) is the process of providing dependencies to an object from outside rather than creating them internally. It promotes loose coupling and testability.

Constructor Injection: Dependencies are injected through the constructor.

public class StudentService {
    private StudentDAO dao;

    public StudentService(StudentDAO dao) {
        this.dao = dao;
    }
}

XML Configuration:

<bean id="service" class="StudentService">
    <constructor-arg ref="dao"/>
</bean>

Setter Injection: Dependencies are injected through setter methods.

public class StudentService {
    private StudentDAO dao;

    public void setDao(StudentDAO dao) {
        this.dao = dao;
    }
}

XML Configuration:

<property name="dao" ref="dao"/>

Comparison:

3. Explain JDBC Statement objects and ResultSet. Mention the purpose of executeQuery(), executeUpdate() and next().

Answer:

Statement Objects:

• Statement: Executes simple SQL queries.
• PreparedStatement: Precompiled SQL with parameters.
• CallableStatement: Calls stored procedures.

ResultSet: Stores the results of a SQL query in tabular form. It maintains a cursor pointing to the current row.

Methods:

Example:

Statement stmt = con.createStatement();

// executeQuery()
ResultSet rs = stmt.executeQuery("SELECT * FROM student");
while (rs.next()) {                        // next()
    System.out.println(rs.getString("name"));
}

// executeUpdate()
int rows = stmt.executeUpdate("DELETE FROM student");
System.out.println(rows + " rows deleted");

4. Explain Inversion of Control and Dependency Injection in Spring. Compare setter injection and field injection.

Answer:

Inversion of Control (IoC): Object creation and dependency management are transferred from the programmer to the Spring container.

Dependency Injection (DI): The process of providing dependencies to an object from outside.

Setter Injection:

public class StudentService {
    private StudentDAO dao;
    public void setDao(StudentDAO dao) {
        this.dao = dao;
    }
}

Field Injection:

@Service
public class StudentService {
    @Autowired
    private StudentDAO dao;
}

Comparison:

Advantages of IoC and DI:

1. Loose coupling
2. Easier testing
3. Better maintainability
4. Reusability
5. Scalability

5. Explain JDBC metadata. Differentiate between DatabaseMetaData and ResultSetMetaData.

Answer:

JDBC Metadata means “data about data.” It provides information about the database structure, tables, columns, and query results.

DatabaseMetaData: Provides information about the database and DBMS.

DatabaseMetaData dm = con.getMetaData();
System.out.println(dm.getDatabaseProductName());  // MySQL

ResultSetMetaData: Provides information about columns in a ResultSet.

ResultSetMetaData meta = rs.getMetaData();
System.out.println(meta.getColumnCount());  // 4
System.out.println(meta.getColumnName(1));  // id
System.out.println(meta.getColumnTypeName(1));  // INT

Comparison:

6. Explain Spring bean scope and bean lifecycle. Mention any four commonly used bean scopes/lifecycle concepts.

Answer:

Bean Scope: Defines how long a bean instance exists in the container.

Bean Lifecycle:

1. Instantiation
2. Dependency Injection
3. @PostConstruct (init)
4. Bean Ready for Use
5. @PreDestroy (destroy)
6. Bean Removed

Lifecycle Callbacks:

@Component
public class Student {
    @PostConstruct
    public void init() {
        System.out.println("Bean initialized");
    }

    @PreDestroy
    public void destroy() {
        System.out.println("Bean destroyed");
    }
}

Four Commonly Used Concepts:

1. Singleton scope — default, one instance
2. Prototype scope — new instance per request
3. @PostConstruct — initialization callback
4. @PreDestroy — destruction callback

7. Explain JDBC exceptions and data types. Discuss the role of SQLException and SQL data types while processing database values in Java.

Answer:

JDBC Exceptions:SQLException is the main exception class in JDBC. It is thrown when database operations fail.

try {
    Connection con = DriverManager.getConnection(url, user, password);
} catch (SQLException e) {
    System.out.println(e.getMessage());
    System.out.println(e.getErrorCode());
    System.out.println(e.getSQLState());
}

JDBC Data Types: JDBC maps SQL data types to Java data types.

Example:

int id = rs.getInt("id");
String name = rs.getString("name");
java.sql.Date d = rs.getDate("dob");

Role of SQLException:

1. Handles database errors
2. Provides error codes and SQL state
3. Enables exception chaining

Role of Data Types:

1. Type mapping between SQL and Java
2. Data conversion
3. Type-safe data retrieval

8. Explain the basic architecture of Spring MVC. Describe the roles of Controller, Model and View in processing a client request.

Answer:

Spring MVC Architecture:

Browser → DispatcherServlet → HandlerMapping → Controller → ViewResolver → View (JSP)

Components:

Flow:

1. Browser sends request to /home
2. DispatcherServlet receives request
3. HandlerMapping finds HomeController
4. Controller method executes, returns "home"
5. ViewResolver maps "home" to /WEB-INF/views/home.jsp
6. JSP renders HTML response
7. Response sent back to browser

Example:

@Controller
public class HomeController {
    @RequestMapping("/home")
    public String home(Model model) {
        model.addAttribute("message", "Welcome");
        return "home";
    }
}

9. Explain the difference between Statement and PreparedStatement in JDBC, highlighting performance and security advantages.

Answer:

Statement Example:

Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM student");

PreparedStatement Example:

PreparedStatement ps = con.prepareStatement(
    "SELECT * FROM student WHERE id=?");
ps.setInt(1, 101);
ResultSet rs = ps.executeQuery();

Security Advantage: PreparedStatement prevents SQL injection by escaping parameters. User input is treated as data, not SQL code.

Performance Advantage: PreparedStatement is precompiled, so repeated execution is faster than Statement.

10. Explain the role of Type 3 and Type 4 JDBC drivers in database connectivity architectures.

Answer:

Type 3: Network Protocol Driver

Architecture:

Java → Middleware Server → Database

Features:

• Uses middleware server
• Database independent
• No client-side installation

Advantages:

• Database independent
• No client-side installation
• Good for web applications

Disadvantages:

• Additional server required
• Extra network hop adds latency

Type 4: Thin Driver (Pure Java)

Architecture:

Java → Database

Example:

Class.forName("com.mysql.cj.jdbc.Driver");

Features:

• Pure Java
• Direct communication with database
• Fastest performance

Advantages:

1. Fastest
2. Pure Java
3. Portable
4. Most commonly used

Comparison:

11. Describe the function of Layout Managers in Java Swing and contrast FlowLayout with BorderLayout.

Answer:

Layout Managers control how components are arranged in a container.

FlowLayout: Arranges components left to right, wrapping to the next line when needed.

frame.setLayout(new FlowLayout());

Example:

[A] [B] [C]
[D] [E]

BorderLayout: Divides the container into five regions: North, South, East, West, Center.

frame.setLayout(new BorderLayout());
frame.add(new JButton("North"), BorderLayout.NORTH);
frame.add(new JButton("Center"), BorderLayout.CENTER);

Example:

        North
West    Center    East
        South

Comparison:

12. Explain the purpose of event adapters in Java Swing and why they are useful when implementing listener interfaces.

Answer:

Event Adapters provide default implementations of listener methods. They are useful because listener interfaces have multiple methods, and you often need only one.

Example — WindowAdapter:

public class Demo extends WindowAdapter {
    public void windowClosing(WindowEvent e) {
        System.exit(0);
    }
}

Without Adapter:

public class Demo implements WindowListener {
    public void windowClosing(WindowEvent e) { System.exit(0); }
    public void windowOpened(WindowEvent e) { }      // Empty
    public void windowClosed(WindowEvent e) { }       // Empty
    public void windowIconified(WindowEvent e) { }    // Empty
    public void windowDeiconified(WindowEvent e) { }  // Empty
    public void windowActivated(WindowEvent e) { }    // Empty
    public void windowDeactivated(WindowEvent e) { }  // Empty
}

Benefits:

1. Less coding
2. Override only required methods
3. Cleaner code
4. Easier maintenance

Common Adapters:

• WindowAdapter
• MouseAdapter
• KeyAdapter
• FocusAdapter

13. Describe the main differences between ApplicationContext and BeanFactory in the Spring IoC container hierarchy.

Answer:

BeanFactory Example:

BeanFactory factory = new XmlBeanFactory(
    new ClassPathResource("beans.xml"));
Student student = (Student) factory.getBean("student");

ApplicationContext Example:

ApplicationContext context =
    new ClassPathXmlApplicationContext("beans.xml");
Student student = context.getBean("student", Student.class);

Key Differences:

1. ApplicationContext is built on top of BeanFactory
2. ApplicationContext supports annotations, events, and i18n
3. BeanFactory is lightweight; ApplicationContext is feature-rich
4. ApplicationContext eagerly initializes beans

14. Explain the function of Spring Stereotype annotations (@Component, @Service, @Repository, @Controller).

Answer:

Spring stereotype annotations mark classes as Spring-managed beans.

Examples:

@Component
public class Student {
}

@Service
public class StudentService {
}

@Repository
public class StudentDAO {
}

@Controller
public class StudentController {
}

How They Work:

1. Component scanning detects these annotations
2. Spring creates bean instances
3. Dependencies are injected
4. Beans are managed by the container

Benefits:

1. Readability — Intent is clear from annotation
2. Specialization — @Repository translates exceptions
3. Convention — Follows layered architecture
4. Reduced Configuration — No XML needed

15. Explain servlet lifecycle phases (init, service, destroy) in a standard J2EE web container environment.

Answer:

The servlet lifecycle has three main phases:

1. init() Called once when the servlet is first loaded.

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

2. service() Called for every request. Dispatches to doGet() or doPost().

public void service(ServletRequest req, ServletResponse res) {
    System.out.println("Processing Request");
}

3. destroy() Called before the servlet is removed.

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

Lifecycle Flow:

Servlet Loaded → init() → service() → service() → ... → destroy()

Example:

import jakarta.servlet.*;

public class LifeCycleDemo extends GenericServlet {
    public void init() {
        System.out.println("init()");
    }
    public void service(ServletRequest req, ServletResponse res) {
        System.out.println("service()");
    }
    public void destroy() {
        System.out.println("destroy()");
    }
}

Key Points:

• init() is called once
• service() is called for each request
• destroy() is called once before removal
• Container manages the lifecycle

16. Compare session tracking mechanisms in J2EE, specifically Cookies versus HttpSession.

Answer:

Cookie Example:

Cookie c = new Cookie("user", "Rahul");
c.setMaxAge(60 * 60 * 24);  // 1 day
response.addCookie(c);

// Reading
Cookie[] cookies = request.getCookies();
for (Cookie ck : cookies) {
    if (ck.getName().equals("user")) {
        String user = ck.getValue();
    }
}

HttpSession Example:

HttpSession session = request.getSession();
session.setAttribute("user", "Rahul");

// Reading
String user = (String) session.getAttribute("user");

When to Use:

• Cookies: Small, non-sensitive data (preferences, theme)
• HttpSession: Sensitive data (login, cart, user info)

Session Tracking Techniques:

1. Cookies
2. HttpSession
3. URL Rewriting
4. Hidden Form Fields

SECTION III: LONG ANSWER QUESTIONS (4 Marks Each)Copy Anchor Link

1. (i) Explain JDBC transaction processing and exception handling. Discuss commit(), rollback(), auto-commit mode and SQLException with suitable examples. (2 marks)

Answer:

Transaction Processing: A transaction is a group of SQL operations executed as a single unit.

ACID Properties:

• Atomicity: All operations succeed or fail together
• Consistency: Database remains valid
• Isolation: Transactions execute independently
• Durability: Changes remain permanent

Auto-commit Mode: By default, JDBC uses auto-commit mode, where each statement is committed automatically.

con.setAutoCommit(false);   // Disable auto-commit

Commit: Saves changes permanently.

con.commit();

Rollback: Undoes changes.

con.rollback();

Complete Example:

try {
    con.setAutoCommit(false);
    stmt.executeUpdate("UPDATE account SET balance=balance-1000 WHERE id=1");
    stmt.executeUpdate("UPDATE account SET balance=balance+1000 WHERE id=2");
    con.commit();
    System.out.println("Transfer successful");
} catch (SQLException e) {
    con.rollback();
    System.out.println("Transfer failed: " + e.getMessage());
}

SQLException: Main exception class in JDBC.

catch (SQLException e) {
    System.out.println("Message: " + e.getMessage());
    System.out.println("Error Code: " + e.getErrorCode());
    System.out.println("SQL State: " + e.getSQLState());
}

Savepoints: Partial rollback points.

Savepoint sp = con.setSavepoint();
con.rollback(sp);

1. (ii) Explain Swing containers and controls. Describe the working of a front-end calculator application using suitable components. (2 marks)

Answer:

Swing Containers:

• JFrame: Top-level container (main window)
• JPanel: Grouping container
• JScrollPane: Scrollable container
• JTabbedPane: Tabbed container

Swing Controls:

• JLabel: Display text/image
• JTextField: Single-line input
• JButton: Clickable button
• JCheckBox: Multiple selections
• JComboBox: Drop-down list

Calculator Application:

Components:

• JTextField for display
• JButtons for digits (0-9) and operations (+, -, *, /, =)
• GridLayout for button arrangement

Layout:

[        10        ]
[7] [8] [9] [ / ]
[4] [5] [6] [ * ]
[1] [2] [3] [ - ]
[0] [.] [=] [ + ]

Code:

JFrame frame = new JFrame("Calculator");
JTextField display = new JTextField();
display.setEditable(false);

JPanel panel = new JPanel();
panel.setLayout(new GridLayout(4, 4, 5, 5));

String[] buttons = {
    "7", "8", "9", "/",
    "4", "5", "6", "*",
    "1", "2", "3", "-",
    "0", ".", "=", "+"
};

for (String text : buttons) {
    JButton btn = new JButton(text);
    btn.addActionListener(e -> {
        // Handle button click
    });
    panel.add(btn);
}

frame.add(display, BorderLayout.NORTH);
frame.add(panel, BorderLayout.CENTER);

Event Handling:

btn.addActionListener(e -> {
    String cmd = btn.getText();
    if (cmd.equals("=")) {
        // Evaluate expression
    } else {
        // Append to expression
    }
});

Working:

1. User clicks buttons to build expression
2. Expression displayed in JTextField
3. “=” evaluates the expression
4. Result displayed

2. (i) Explain Spring architecture and Inversion of Control. Discuss bean scope and bean lifecycle, including the major stages from bean creation to destruction. (2 marks)

Answer:

Spring Architecture:

Application
    |
--------------------------------
| Core Container               |
| Data Access Layer            |
| Web Layer                    |
| Integration Layer            |
--------------------------------

Core Container:

• BeanFactory
• ApplicationContext
• IoC Container

Inversion of Control (IoC): Object creation and dependency management transferred to Spring container.

Traditional:

StudentDAO dao = new StudentDAO();

Spring:

@Autowired
StudentDAO dao;

Bean Scope: | Scope | Description | |——-|————-| | Singleton | One instance (default) | | Prototype | New instance per request | | Request | One per HTTP request | | Session | One per HTTP session |

Bean Lifecycle:

1. Instantiation
2. Dependency Injection
3. @PostConstruct (init)
4. Bean Ready for Use
5. @PreDestroy (destroy)
6. Bean Removed

Example:

@Component
public class Student {
    public Student() {
        System.out.println("1. Constructor");
    }

    @Autowired
    public void setDao(StudentDAO dao) {
        System.out.println("2. Setter");
    }

    @PostConstruct
    public void init() {
        System.out.println("3. Init");
    }

    @PreDestroy
    public void destroy() {
        System.out.println("4. Destroy");
    }
}

Output (context start):

1. Constructor
2. Setter
3. Init

Output (context close):

4. Destroy

2. (ii) Explain the configuration of Spring MVC and the role of @RequestMapping in handling client requests. (2 marks)

Answer:

Spring MVC Configuration:

1. DispatcherServlet (web.xml):

<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>
        org.springframework.web.servlet.DispatcherServlet
    </servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

2. Component Scanning:

<context:component-scan base-package="com.demo"/>

3. View Resolver:

<bean class="InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/views/"/>
    <property name="suffix" value=".jsp"/>
</bean>

@RequestMapping: Maps URL requests to controller methods.

Class Level:

@Controller
@RequestMapping("/student")
public class StudentController {
}

Method Level:

@RequestMapping("/list")
public String list() {
    return "list";
}

With HTTP Method:

@RequestMapping(value="/save", method=RequestMethod.POST)
public String save() {
    return "success";
}

Specialized Annotations:

@GetMapping("/list")     // GET
@PostMapping("/save")    // POST
@PutMapping("/update")   // PUT
@DeleteMapping("/delete") // DELETE

Request Flow:

Browser → DispatcherServlet → HandlerMapping → Controller → ViewResolver → View

Example:

@Controller
public class HomeController {
    @RequestMapping("/home")
    public String home(Model model) {
        model.addAttribute("message", "Welcome");
        return "home";
    }
}

URL: http://localhost:8080/home → home.jsp

3. (i) Explain ResultSet and JDBC metadata. Discuss ResultSetMetaData and DatabaseMetaData with suitable examples. (2 marks)

Answer:

ResultSet: Stores the results of a SQL query. Maintains a cursor pointing to the current row.

ResultSet rs = stmt.executeQuery("SELECT * FROM student");
while (rs.next()) {
    System.out.println(rs.getString("name"));
}

ResultSetMetaData: Provides information about columns in a ResultSet.

ResultSetMetaData meta = rs.getMetaData();
int count = meta.getColumnCount();
for (int i = 1; i <= count; i++) {
    System.out.println("Column: " + meta.getColumnName(i));
    System.out.println("Type: " + meta.getColumnTypeName(i));
}

Output:

Column: id
Type: INT
Column: name
Type: VARCHAR
...

DatabaseMetaData: Provides information about the database and DBMS.

DatabaseMetaData dm = con.getMetaData();
System.out.println(dm.getDatabaseProductName());  // MySQL
System.out.println(dm.getDatabaseProductVersion());
System.out.println(dm.getDriverName());

Listing Tables:

ResultSet tables = dm.getTables(null, null, "%", null);
while (tables.next()) {
    System.out.println(tables.getString("TABLE_NAME"));
}

Comparison:

3. (ii) Explain the role of Swing controls and containers in a calculator application. Discuss event handling and basic database connectivity considerations. (2 marks)

Answer:

Swing Controls in Calculator:

• JTextField: Display area
• JButton: Digits and operations
• JPanel: Button grouping

Swing Containers:

• JFrame: Main window
• JPanel: Button panel with GridLayout

Layout:

JFrame frame = new JFrame("Calculator");
JTextField display = new JTextField();
display.setEditable(false);

JPanel panel = new JPanel();
panel.setLayout(new GridLayout(4, 4, 5, 5));

String[] buttons = {
    "7", "8", "9", "/",
    "4", "5", "6", "*",
    "1", "2", "3", "-",
    "0", ".", "=", "+"
};

for (String text : buttons) {
    JButton btn = new JButton(text);
    btn.addActionListener(e -> handleClick(btn.getText()));
    panel.add(btn);
}

Event Handling:

private void handleClick(String cmd) {
    if (cmd.equals("=")) {
        try {
            double result = evaluate(expression);
            display.setText(String.valueOf(result));
        } catch (Exception e) {
            display.setText("Error");
        }
    } else {
        expression += cmd;
        display.setText(expression);
    }
}

Database Connectivity Considerations:

• Calculator typically doesn’t need DB
• If storing history:
  • Use JDBC to save calculations
  • Table: history(id, expression, result, timestamp)
  • Use PreparedStatement for insertion

PreparedStatement ps = con.prepareStatement(
    "INSERT INTO history(expression, result) VALUES(?, ?)");
ps.setString(1, expression);
ps.setDouble(2, result);
ps.executeUpdate();

Key Considerations:

1. Use EDT for Swing updates
2. Handle exceptions gracefully
3. Close DB resources
4. Validate input

4. (i) Describe database connection creation in JDBC using DriverManager and Connection. Explain JDBC packages, driver registration and the role of the JDBC/ODBC bridge. (2 marks)

Answer:

DriverManager: Class used to create database connections.

Connection con = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/test", "root", "root");

Connection: Represents an active session with the database.

Connection con = DriverManager.getConnection(url, user, password);

JDBC Packages: | Package | Purpose | |———|———| | java.sql | Core JDBC classes and interfaces | | javax.sql | Advanced features (connection pooling, DataSource) |

Driver Registration:

Class.forName("com.mysql.cj.jdbc.Driver");

Modern JDBC 4.0+ auto-registers drivers found on the classpath.

JDBC/ODBC Bridge:

Java → JDBC → ODBC → Database

Features:

• Type 1 driver
• Uses ODBC
• Easy to configure
• Slow performance

Example:

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

Limitations:

1. Platform dependent
2. Requires ODBC installation
3. Removed after Java 8

Connection URL Components:

jdbc:mysql://host:port/database

4. (ii) Explain the design of a database application using Java Swing. Describe how the GUI communicates with a database. (2 marks)

Answer:

Design:

┌─────────────────┐
│   Swing UI      │
└────────┬────────┘
         ↓
┌─────────────────┐
│   DAO Layer     │
└────────┬────────┘
         ↓
┌─────────────────┐
│   Database      │
└─────────────────┘

Components:

• JFrame: Main window
• JTextField: Input fields
• JButton: Actions (Save, Update, Delete)
• JTable: Display records

GUI Design:

JFrame f = new JFrame("Student Management");
JLabel l1 = new JLabel("Name:");
JTextField tf1 = new JTextField();
JLabel l2 = new JLabel("Age:");
JTextField tf2 = new JTextField();
JButton save = new JButton("Save");
JTable table = new JTable(model);

Communication Flow:

1. User enters data in JTextField
2. User clicks JButton
3. ActionListener triggers DAO method
4. DAO executes SQL via JDBC
5. Result returned to GUI
6. JTable/JOptionPane displays result

Example:

save.addActionListener(e -> {
    try {
        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection con = DriverManager.getConnection(
            "jdbc:mysql://localhost:3306/school", "root", "root");

        PreparedStatement ps = con.prepareStatement(
            "INSERT INTO student(name, age) VALUES(?, ?)");
        ps.setString(1, tf1.getText());
        ps.setInt(2, Integer.parseInt(tf2.getText()));
        ps.executeUpdate();

        JOptionPane.showMessageDialog(f, "Saved!");
        con.close();
    } catch (Exception ex) {
        JOptionPane.showMessageDialog(f, "Error: " + ex.getMessage());
    }
});

Best Practices:

1. Use PreparedStatement (prevent SQL injection)
2. Close resources (try-with-resources)
3. Use SwingUtilities.invokeLater for thread safety
4. Handle exceptions with user-friendly messages
5. Use connection pooling for performance

5. (i) Explain the Spring bean lifecycle and different bean scopes. Describe constructor injection, setter injection and field injection with suitable examples. (2 marks)

Answer:

Bean Scopes: | Scope | Description | |——-|————-| | Singleton | One instance per container (default) | | Prototype | New instance per request | | Request | One per HTTP request | | Session | One per HTTP session |

Bean Lifecycle:

1. Instantiation
2. Dependency Injection
3. @PostConstruct
4. Bean Ready
5. @PreDestroy
6. Bean Removed

Injection Types:

Constructor Injection:

public class StudentService {
    private final StudentDAO dao;

    public StudentService(StudentDAO dao) {
        this.dao = dao;
    }
}

Setter Injection:

public class StudentService {
    private StudentDAO dao;

    public void setDao(StudentDAO dao) {
        this.dao = dao;
    }
}

Field Injection:

@Service
public class StudentService {
    @Autowired
    private StudentDAO dao;
}

Comparison:

Advantages of IoC and DI:

1. Loose coupling
2. Easier testing
3. Better maintainability
4. Reusability
5. Scalability

5. (ii) Explain Spring MVC request processing and @RequestMapping. Discuss the basic configuration required for an MVC application. (2 marks)

Answer:

Request Processing Flow:

Browser → DispatcherServlet → HandlerMapping → Controller → ViewResolver → View

Steps:

1. Browser sends request
2. DispatcherServlet receives request
3. HandlerMapping finds controller
4. Controller method executes
5. Returns view name
6. ViewResolver maps to JSP
7. JSP renders HTML
8. Response sent to browser

@RequestMapping: Maps URL requests to controller methods.

Class Level:

@Controller
@RequestMapping("/student")
public class StudentController {
}

Method Level:

@RequestMapping("/list")
public String list() {
    return "list";
}

With HTTP Method:

@RequestMapping(value="/save", method=RequestMethod.POST)

Specialized:

@GetMapping("/list")
@PostMapping("/save")
@PutMapping("/update")
@DeleteMapping("/delete")

Basic Configuration:

web.xml:

<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>
        org.springframework.web.servlet.DispatcherServlet
    </servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

Spring Config:

<context:component-scan base-package="com.demo"/>

<bean class="InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/views/"/>
    <property name="suffix" value=".jsp"/>
</bean>

Controller:

@Controller
public class HomeController {
    @RequestMapping("/home")
    public String home(Model model) {
        model.addAttribute("message", "Welcome");
        return "home";
    }
}

6. (i) Explain Spring MVC form handling using the Form Tag Library and validation support. (2 marks)

Answer:

Form Tag Library:

<%@ taglib prefix="form"
    uri="http://www.springframework.org/tags/form"%>

Form Tags: | Tag | Purpose | |—–|———| | <form:form> | Form container | | <form:input> | Text input | | <form:password> | Password input | | <form:textarea> | Multi-line text | | <form:checkbox> | Checkbox | | <form:radiobutton> | Radio button | | <form:select> | Dropdown | | <form:errors> | Display errors |

Example Form:

<form:form modelAttribute="student" action="save" method="post">
    Name: <form:input path="name"/>
    <form:errors path="name" cssClass="error"/><br/>

    Email: <form:input path="email"/>
    <form:errors path="email" cssClass="error"/><br/>

    Age: <form:input path="age"/>
    <form:errors path="age" cssClass="error"/><br/>

    <input type="submit" value="Save"/>
</form:form>

Validation Annotations:

public class Student {
    @NotEmpty(message = "Name is required")
    private String name;

    @Email(message = "Invalid email")
    private String email;

    @Min(value = 18, message = "Age must be at least 18")
    private int age;
}

Controller:

@PostMapping("/save")
public String save(@Valid @ModelAttribute("student") Student student,
                   BindingResult result) {
    if (result.hasErrors()) {
        return "form";
    }
    return "success";
}

Flow:

1. User fills form
2. Submits POST request
3. Spring binds data to Student object
4. @Valid triggers validation
5. If errors → BindingResult has errors → return to form
6. If valid → process → return success

Advantages:

1. Automatic data binding
2. Declarative validation
3. Error display
4. Reusable

6. (ii) Explain bean scopes and lifecycle callbacks in Spring with suitable examples. (2 marks)

Answer:

Bean Scopes:

Example:

@Component
@Scope("singleton")
public class Student {
}

@Component
@Scope("prototype")
public class Employee {
}

Lifecycle Callbacks:

@PostConstruct: Called after bean initialization.

@PostConstruct
public void init() {
    System.out.println("Bean initialized");
}

@PreDestroy: Called before bean destruction.

@PreDestroy
public void destroy() {
    System.out.println("Bean destroyed");
}

Complete Example:

@Component
@Scope("singleton")
public class Student {

    public Student() {
        System.out.println("1. Constructor");
    }

    @Autowired
    public void setDao(StudentDAO dao) {
        System.out.println("2. Setter");
    }

    @PostConstruct
    public void init() {
        System.out.println("3. Init");
    }

    @PreDestroy
    public void destroy() {
        System.out.println("4. Destroy");
    }
}

Output:

1. Constructor
2. Setter
3. Init
(bean in use)
4. Destroy

Lifecycle Phases:

1. Instantiation
2. Dependency Injection
3. @PostConstruct
4. Bean Ready
5. @PreDestroy
6. Bean Removed

7. (i) Explain the complete JDBC database access procedure, including connection establishment, Statement creation, SQL execution, ResultSet processing, closing resources and exception handling. (2 marks)

Answer:

Complete JDBC Procedure:

Step 1: Load Driver

Class.forName("com.mysql.cj.jdbc.Driver");

Step 2: Establish Connection

Connection con = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/test", "root", "root");

Step 3: Create Statement

Statement stmt = con.createStatement();

Step 4: Execute Query

ResultSet rs = stmt.executeQuery("SELECT * FROM student");

Step 5: Process ResultSet

while (rs.next()) {
    System.out.println(rs.getInt("id") + " " + rs.getString("name"));
}

Step 6: Close Resources

rs.close();
stmt.close();
con.close();

Step 7: Exception Handling

try {
    // JDBC operations
} catch (SQLException e) {
    e.printStackTrace();
} catch (ClassNotFoundException e) {
    System.out.println("Driver not found");
}

Complete Program:

import java.sql.*;

public class JdbcExample {
    public static void main(String[] args) {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            try (Connection con = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/test", "root", "root");
                 Statement stmt = con.createStatement();
                 ResultSet rs = stmt.executeQuery("SELECT * FROM student")) {

                while (rs.next()) {
                    System.out.println(rs.getInt("id") + " " + rs.getString("name"));
                }
            }
        } catch (ClassNotFoundException e) {
            System.out.println("Driver not found");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

try-with-resources: Automatically closes resources.

try (Connection con = ...;
     Statement stmt = ...;
     ResultSet rs = ...) {
    // Use resources
}   // Auto-close

Best Practices:

1. Use Type 4 driver
2. Use PreparedStatement
3. Close resources
4. Handle exceptions
5. Use connection pooling

7. (ii) Explain the structure of a Java Swing front-end application. Describe a calculator case study using containers, controls and event handling. (2 marks)

Answer:

Swing Application Structure:

JFrame (Main Window)
    ├── JPanel (Container)
    │   ├── JLabel
    │   ├── JTextField
    │   └── JButton
    └── JPanel (Another Container)
        └── JTable

Calculator Case Study:

Components:

• JFrame: Main window
• JTextField: Display
• JButton: Digits and operations
• JPanel: Button grouping
• GridLayout: Button arrangement

Code:

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

public class Calculator {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Calculator");
        JTextField display = new JTextField();
        display.setEditable(false);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(4, 4, 5, 5));

        String[] buttons = {
            "7", "8", "9", "/",
            "4", "5", "6", "*",
            "1", "2", "3", "-",
            "0", ".", "=", "+"
        };

        StringBuilder expression = new StringBuilder();

        for (String text : buttons) {
            JButton btn = new JButton(text);
            btn.addActionListener(e -> {
                String cmd = btn.getText();
                if (cmd.equals("=")) {
                    try {
                        double result = evaluate(expression.toString());
                        display.setText(String.valueOf(result));
                        expression.setLength(0);
                    } catch (Exception ex) {
                        display.setText("Error");
                    }
                } else {
                    expression.append(cmd);
                    display.setText(expression.toString());
                }
            });
            panel.add(btn);
        }

        frame.add(display, BorderLayout.NORTH);
        frame.add(panel, BorderLayout.CENTER);
        frame.setSize(300, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

Event Handling:

• Each button has an ActionListener
• Lambda expression handles clicks
• = evaluates expression
• Other buttons append to expression

Layout:

[        10        ]
[7] [8] [9] [ / ]
[4] [5] [6] [ * ]
[1] [2] [3] [ - ]
[0] [.] [=] [ + ]

Key Concepts:

1. JFrame as top-level container
2. JPanel for grouping
3. GridLayout for buttons
4. ActionListener for events
5. JTextField for display

8. (i) Explain Dependency Injection in Spring with constructor, setter and field injection. State the advantages of using IoC and DI in application development. (2 marks)

Answer:

Dependency Injection (DI): Process of providing dependencies to an object from outside.

Constructor Injection:

public class StudentService {
    private final StudentDAO dao;

    public StudentService(StudentDAO dao) {
        this.dao = dao;
    }
}

Setter Injection:

public class StudentService {
    private StudentDAO dao;

    public void setDao(StudentDAO dao) {
        this.dao = dao;
    }
}

Field Injection:

@Service
public class StudentService {
    @Autowired
    private StudentDAO dao;
}

Comparison:

Advantages of IoC and DI:

1. Loose Coupling: Objects don’t create their dependencies
2. Easier Testing: Dependencies can be mocked
3. Better Maintainability: Changes in one place
4. Reusability: Beans can be reused
5. Scalability: Container manages resources
6. Configuration Flexibility: XML, annotations, Java config
7. Lifecycle Management: Container manages bean lifecycle

Example:

// Without DI (tight coupling)
public class StudentService {
    private StudentDAO dao = new StudentDAO();
}

// With DI (loose coupling)
@Service
public class StudentService {
    @Autowired
    private StudentDAO dao;
}

8. (ii) Explain Spring MVC Form Tag Library and Spring Validation. Describe how a form is submitted and validated in a controller. (2 marks)

Answer:

Form Tag Library:

<%@ taglib prefix="form"
    uri="http://www.springframework.org/tags/form"%>

Tags: | Tag | Purpose | |—–|———| | <form:form> | Form container | | <form:input> | Text input | | <form:errors> | Display errors | | <form:select> | Dropdown | | <form:checkbox> | Checkbox |

Form Example:

<form:form modelAttribute="student" action="save" method="post">
    Name: <form:input path="name"/>
    <form:errors path="name" cssClass="error"/><br/>

    Email: <form:input path="email"/>
    <form:errors path="email" cssClass="error"/><br/>

    <input type="submit" value="Save"/>
</form:form>

Validation Annotations:

public class Student {
    @NotEmpty(message = "Name is required")
    private String name;

    @Email(message = "Invalid email")
    private String email;

    @Min(value = 18, message = "Age must be at least 18")
    private int age;
}

Controller:

@PostMapping("/save")
public String save(@Valid @ModelAttribute("student") Student student,
                   BindingResult result) {
    if (result.hasErrors()) {
        return "form";
    }
    return "success";
}

Form Submission Flow:

1. User opens form (GET /form)
2. Controller adds empty Student to model
3. Form displayed
4. User fills form → POST /save
5. Spring binds data to Student object
6. @Valid triggers validation
7. If errors → BindingResult has errors → return to form
8. If valid → process data → return success

Advantages:

1. Automatic data binding
2. Declarative validation
3. Error display
4. Type safety

9. (i) Explain JDBC transaction processing and exception handling. Discuss commit(), rollback() and SQLException. (2 marks)

Answer:

Transaction Processing: A transaction is a group of SQL operations executed as a single unit.

ACID Properties:

• Atomicity: All operations succeed or fail together
• Consistency: Database remains valid
• Isolation: Transactions execute independently
• Durability: Changes remain permanent

Auto-commit Mode: By default, JDBC uses auto-commit mode.

con.setAutoCommit(false);  // Disable

Commit: Saves changes permanently.

con.commit();

Rollback: Undoes changes.

con.rollback();

Example:

try {
    con.setAutoCommit(false);
    stmt.executeUpdate("UPDATE account SET balance=balance-1000 WHERE id=1");
    stmt.executeUpdate("UPDATE account SET balance=balance+1000 WHERE id=2");
    con.commit();
    System.out.println("Transfer successful");
} catch (SQLException e) {
    con.rollback();
    System.out.println("Transfer failed: " + e.getMessage());
}

SQLException: Main exception class in JDBC.

catch (SQLException e) {
    System.out.println("Message: " + e.getMessage());
    System.out.println("Error Code: " + e.getErrorCode());
    System.out.println("SQL State: " + e.getSQLState());
}

Savepoints: Partial rollback points.

Savepoint sp = con.setSavepoint();
con.rollback(sp);

Best Practices:

1. Disable auto-commit for transactions
2. Commit on success
3. Rollback on error
4. Close resources
5. Handle SQLException

9. (ii) Explain Spring MVC request mapping and form validation with a suitable application flow. (2 marks)

Answer:

Request Mapping: Maps URL requests to controller methods.

Class Level:

@Controller
@RequestMapping("/student")
public class StudentController {
}

Method Level:

@RequestMapping("/list")
public String list() {
    return "list";
}

Specialized:

@GetMapping("/list")
@PostMapping("/save")
@PutMapping("/update")
@DeleteMapping("/delete")

Form Validation:

public class Student {
    @NotEmpty(message = "Name is required")
    private String name;

    @Email(message = "Invalid email")
    private String email;
}

Controller:

@PostMapping("/save")
public String save(@Valid @ModelAttribute("student") Student student,
                   BindingResult result) {
    if (result.hasErrors()) {
        return "form";
    }
    return "success";
}

Application Flow:

1. User opens /student/form (GET)
2. Controller adds empty Student to model
3. Form displayed with form tags
4. User fills form → POST /student/save
5. Spring binds data to Student object
6. @Valid triggers validation
7. If errors → BindingResult has errors → return "form"
8. If valid → process data → return "success"
9. ViewResolver maps to success.jsp
10. Success page displayed

Example:

@Controller
@RequestMapping("/student")
public class StudentController {

    @GetMapping("/form")
    public String showForm(Model model) {
        model.addAttribute("student", new Student());
        return "form";
    }

    @PostMapping("/save")
    public String save(@Valid @ModelAttribute("student") Student student,
                       BindingResult result) {
        if (result.hasErrors()) {
            return "form";
        }
        return "success";
    }
}

Advantages:

1. Declarative mapping
2. Automatic data binding
3. Validation support
4. Error handling

10. (i) Explain JDBC transaction management with a suitable example. Discuss auto-commit, commit, rollback and exception handling in a database application. (2 marks)

Answer:

Transaction Management: A transaction is a group of SQL operations executed as a single unit.

Auto-commit: By default, each statement is committed automatically.

con.setAutoCommit(false);  // Disable

Commit: Saves changes permanently.

con.commit();

Rollback: Undoes changes.

con.rollback();

Example — Bank Transfer:

import java.sql.*;

public class BankTransfer {
    public static void main(String[] args) {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            Connection con = DriverManager.getConnection(
                "jdbc:mysql://localhost:3306/bank", "root", "root");

            con.setAutoCommit(false);

            try {
                PreparedStatement debit = con.prepareStatement(
                    "UPDATE account SET balance=balance-? WHERE id=?");
                debit.setDouble(1, 1000);
                debit.setInt(2, 1);
                debit.executeUpdate();

                PreparedStatement credit = con.prepareStatement(
                    "UPDATE account SET balance=balance+? WHERE id=?");
                credit.setDouble(1, 1000);
                credit.setInt(2, 2);
                credit.executeUpdate();

                con.commit();
                System.out.println("Transfer successful");
            } catch (SQLException e) {
                con.rollback();
                System.out.println("Transfer failed. Rolled back.");
            }

            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Exception Handling:

catch (SQLException e) {
    System.out.println("Error: " + e.getMessage());
    System.out.println("Code: " + e.getErrorCode());
    System.out.println("State: " + e.getSQLState());
}

ACID Properties:

• Atomicity: Both updates succeed or fail together
• Consistency: Total balance remains unchanged
• Isolation: Transaction is independent
• Durability: Changes persist after commit

Savepoints:

Savepoint sp = con.setSavepoint();
con.rollback(sp);

10. (ii) Explain a Swing-based database application. Describe the steps for creating a GUI, accepting user input and performing database operations. (2 marks)

Answer:

Swing-Based Database Application:

Steps:

Step 1: Create GUI

JFrame f = new JFrame("Student Management");
JLabel l1 = new JLabel("Name:");
JTextField tf1 = new JTextField();
JLabel l2 = new JLabel("Age:");
JTextField tf2 = new JTextField();
JButton save = new JButton("Save");
JButton view = new JButton("View All");
JTable table = new JTable(model);

Step 2: Layout Components

f.setLayout(new BorderLayout());
JPanel formPanel = new JPanel(new GridLayout(3, 2));
formPanel.add(l1); formPanel.add(tf1);
formPanel.add(l2); formPanel.add(tf2);
formPanel.add(save);
f.add(formPanel, BorderLayout.NORTH);
f.add(new JScrollPane(table), BorderLayout.CENTER);

Step 3: Accept User Input

String name = tf1.getText();
int age = Integer.parseInt(tf2.getText());

Step 4: Perform Database Operations

save.addActionListener(e -> {
    try {
        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection con = DriverManager.getConnection(
            "jdbc:mysql://localhost:3306/school", "root", "root");

        PreparedStatement ps = con.prepareStatement(
            "INSERT INTO student(name, age) VALUES(?, ?)");
        ps.setString(1, tf1.getText());
        ps.setInt(2, Integer.parseInt(tf2.getText()));
        ps.executeUpdate();

        JOptionPane.showMessageDialog(f, "Saved!");
        con.close();
    } catch (Exception ex) {
        JOptionPane.showMessageDialog(f, "Error: " + ex.getMessage());
    }
});