Sunday, May 10, 2026

JAVA_Chapter6

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UNIT 6 — INTRODUCING SWING AND JDBC

6.1 Design Philosophy of Swing

Swing

Swing is a Java GUI toolkit used to create desktop applications.

Features of Swing

  • Platform independent
  • Lightweight components
  • Rich GUI components
  • Event driven
  • Customizable

AWT vs Swing

AWT Swing
heavyweight lightweight
less components more components
platform dependent platform independent
uses native OS controls pure Java components

Importing Swing Package

import javax.swing.*;

6.2 Components and Containers

Component

GUI element used in application.

Examples

  • JButton
  • JTextField
  • JLabel
  • JCheckBox
  • JList

Container

Container holds components.

Examples

  • JFrame
  • JPanel
  • JDialog

JFrame

Main window of Swing application.

Creating JFrame

import javax.swing.*;

class Test{

   public static void main(String args[]){

      JFrame f =
      new JFrame("My Frame");

      f.setSize(400,300);

      f.setVisible(true);
   }
}

Important JFrame Methods

Method Purpose
setSize() sets frame size
setVisible() shows frame
setTitle() sets title
setLayout() sets layout
add() adds component
setDefaultCloseOperation() closes frame properly

6.3 Layout Managers

Layout Manager

Controls arrangement of components.

Types of Layout Managers

Layout Description
FlowLayout left to right arrangement
BorderLayout north, south, east, west, center
GridLayout rows and columns
CardLayout multiple screens/cards
BoxLayout horizontal/vertical layout

FlowLayout Example

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

class Test{

   public static void main(String args[]){

      JFrame f = new JFrame();

      f.setLayout(new FlowLayout());

      f.add(new JButton("One"));
      f.add(new JButton("Two"));

      f.setSize(300,300);
      f.setVisible(true);
   }
}

BorderLayout Example

f.setLayout(new BorderLayout());

f.add(new JButton("North"),
BorderLayout.NORTH);

f.add(new JButton("South"),
BorderLayout.SOUTH);

GridLayout Example

f.setLayout(new GridLayout(2,2));

6.4 Swing Event Handling

Event

An event is an action performed by user.

Examples

  • Button click
  • Mouse click
  • Keyboard press

Event Handling Process

User Action
     ↓
Event Generated
     ↓
Listener Handles Event

Event Listener

Object that handles events.

ActionListener Interface

import java.awt.event.*;

actionPerformed() Method

public void actionPerformed(
ActionEvent e){
}

Button Event Example

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

class Test implements ActionListener{

   JFrame f;
   JButton b;

   Test(){

      f = new JFrame();

      b = new JButton("Click");

      b.setBounds(100,100,100,40);

      b.addActionListener(this);

      f.add(b);

      f.setSize(300,300);
      f.setLayout(null);
      f.setVisible(true);
   }

   public void actionPerformed(
   ActionEvent e){

      System.out.println("Button Clicked");
   }

   public static void main(
   String args[]){

      new Test();
   }
}

Important Event Classes

Event Listener
ActionEvent ActionListener
MouseEvent MouseListener
KeyEvent KeyListener
WindowEvent WindowListener

6.5 Basic Swing Components

JButton

Creates button.

JButton b =
new JButton("Save");

JTextField

Single line text input.

JTextField t =
new JTextField();

JCheckBox

Creates checkbox.

JCheckBox c =
new JCheckBox("Java");

JList

Displays list items.

String data[] =
{"C","Java","Python"};

JList l =
new JList(data);

JLabel

Displays text label.

JLabel l =
new JLabel("Name");

Simple Form Example

import javax.swing.*;

class Test{

   public static void main(
   String args[]){

      JFrame f = new JFrame();

      JLabel l =
      new JLabel("Name");

      JTextField t =
      new JTextField();

      JButton b =
      new JButton("Submit");

      l.setBounds(50,50,100,30);
      t.setBounds(150,50,100,30);
      b.setBounds(100,100,100,30);

      f.add(l);
      f.add(t);
      f.add(b);

      f.setSize(300,300);
      f.setLayout(null);
      f.setVisible(true);
   }
}

6.6 Anonymous Inner Classes to Handle Events

Anonymous Inner Class

Class without name.

Button Event Using Anonymous Class

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

class Test{

   public static void main(
   String args[]){

      JFrame f = new JFrame();

      JButton b =
      new JButton("Click");

      b.setBounds(100,100,100,40);

      b.addActionListener(
      new ActionListener(){

         public void actionPerformed(
         ActionEvent e){

            System.out.println(
            "Button Clicked");
         }
      });

      f.add(b);

      f.setSize(300,300);
      f.setLayout(null);
      f.setVisible(true);
   }
}

Advantages of Anonymous Inner Class

  • Less code
  • Easy event handling
  • No separate class needed

6.7 The Design of JDBC

JDBC

JDBC stands for Java Database Connectivity.

Purpose of JDBC

  • Connect Java with database
  • Execute SQL queries
  • Perform CRUD operations

JDBC Architecture

Java Application
       ↓
JDBC API
       ↓
JDBC Driver
       ↓
Database

Important JDBC Classes and Interfaces

Class/Interface Purpose
DriverManager manages drivers
Connection database connection
Statement execute SQL query
PreparedStatement parameterized query
ResultSet stores query result

Steps to Connect Database

  1. Import package
  2. Load driver
  3. Create connection
  4. Create statement
  5. Execute query
  6. Close connection

Import JDBC Package

import java.sql.*;

Loading Driver

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

Creating Connection

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

6.8 Executing SQL Statements

Creating Statement

Statement st =
con.createStatement();

executeUpdate()

Used for INSERT, UPDATE, DELETE.

Insert Example

st.executeUpdate(
"insert into student values
(1,'Ram')");

Update Example

st.executeUpdate(
"update student set name='Hari'
where id=1");

Delete Example

st.executeUpdate(
"delete from student
where id=1");

PreparedStatement

Used for dynamic and secure query.

PreparedStatement Example

PreparedStatement ps =
con.prepareStatement(
"insert into student values(?,?)");

ps.setInt(1,1);
ps.setString(2,"Ram");

ps.executeUpdate();

Advantages of PreparedStatement

  • Faster execution
  • Secure against SQL injection
  • Dynamic query support

6.9 Query Execution

executeQuery()

Used for SELECT query.

SELECT Example

ResultSet rs =
st.executeQuery(
"select * from student");

while(rs.next()){

   System.out.println(
   rs.getInt(1)+" "+
   rs.getString(2));
}

ResultSet Methods

Method Purpose
next() moves next row
getInt() gets integer value
getString() gets string value
getDouble() gets double value

Closing Connection

con.close();

Complete JDBC CRUD Example

import java.sql.*;

class Test{

   public static void main(
   String args[])throws Exception{

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

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

      Statement st =
      con.createStatement();

      st.executeUpdate(
      "insert into student values
      (1,'Ram')");

      ResultSet rs =
      st.executeQuery(
      "select * from student");

      while(rs.next()){

         System.out.println(
         rs.getInt(1)+" "+
         rs.getString(2));
      }

      con.close();
   }
}

Most Important Practical Programs

  1. Simple JFrame program
  2. FlowLayout program
  3. GridLayout program
  4. Button click event handling
  5. Anonymous inner class event handling
  6. JTextField form program
  7. JCheckBox program
  8. Database connection program
  9. Insert query using JDBC
  10. Select query using ResultSet
  11. CRUD operations using JDBC

Most Important Theory Questions

  • What is Swing?
  • Difference between AWT and Swing.
  • Explain layout managers.
  • Explain event handling.
  • What is ActionListener?
  • Explain anonymous inner class.
  • What is JDBC?
  • Explain JDBC architecture.
  • Explain steps to connect database.
  • Difference between Statement and PreparedStatement.
  • Explain ResultSet.

Important Viva Questions

Which package is used for Swing?

javax.swing

Which package is used for JDBC?

java.sql

Which class creates main window?

JFrame

Which layout arranges components left to right?

FlowLayout

Which method handles button click event?

actionPerformed()

Which interface handles button event?

ActionListener

Which method executes SELECT query?

executeQuery()

Which method executes INSERT query?

executeUpdate()

Which object stores SELECT query result?

ResultSet
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