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You are already familiar with an HTML class, but JavaScript also has a class. In JavaScript, a class is like a blueprint for creating objects. It allows you to define a set of properties and methods, and instantiate (or create) new objects with those properties and methods.

The class keyword is used to declare a class. Here is an example of declaring a Computer class:

Example Code
class Computer {};

Classes have a special constructor method, which is called when a new instance of the class is created. The constructor method is a great place to initialize properties of the class. Here is an example of a class with a constructor method:

Example Code
class Computer {
  constructor() {
  }
}

The this keyword in JavaScript is used to refer to the current object. Depending on where this is used, what it references changes. In the case of a class, it refers to the instance of the object being constructed. You can use the this keyword to set the properties of the object being instantiated. Here is an example:

Example Code
class Computer {
  constructor() {
    this.ram = 16;
  }
}

Here is an example of instantiating the Computer class from earlier examples:

Example Code
const myComputer = new Computer();

REGISTRATIONS

@user01

<Html>  
<head>   
<title>  
Registration Page  
</title>  
</head>  
<body bgcolor="#96D4D4">
<h1>Registration Form</h1>  
<br>  
<form>  
  
<label> Username </label>         
<input type="text" id = "U1" size="15"/> <br> <br>  
<label> Password: </label>     
<input type="password" password="p1" size="15"/> <br> <br>  
  
<label>   
Course :  
</label>   
<select>  
<option value="Course">Course</option>  
<option value="CSE">CSE</option>  
<option value="IT">IT</option>  
<option value="ECE">ECE</option>  
<option value="EEE">EEE</option>  
<option value="CSM">CSM</option>  
<option value="CSD">CSD</option>  
</select>  
<br>  
<br>
<label>   
Section :  
</label><br>  
<input type="radio" name="A"/> A <br>  
<input type="radio" name="B"/> B <br>  <br>
  
<label>   
Gender :  
</label><br>  
<input type="radio" name="male"/> Male <br>  
<input type="radio" name="female"/> Female <br>  
<input type="radio" name="other"/> Other  
<br>  
<br>  
  
<label for="phone">phone:</label>
<input type="text" name="country code"  value="+91" size="2"/>   
<input type="tel" id="phone" name="phone" pattern="[0-9]{3}-[0-9]{2}-[0-9]{3}" size="10"> <br><br>

<label>   
Mail :  
</label><br>  
<input type="email" id="email "name="email"/> <br>  <br>

<label>
State :
</label>
<select>
<option value = "select">select <br>
<option value = "TS">TS <br>
<option value = "AP">AP <br>
<option value = "TN">TN <br>
<option value = "KR">KR <br>
<option value = "BR">BR <br> <br>
</select> <br><br>
<input type="button" value="Submit"/>  
</form> 
 
</body>  
</html>

#python

Guía de inicio rápido: Envía solicitudes a la API de Vertex AI para Gemini | Generative AI on Vertex AI | Google Cloud

@Spsypg

import vertexai
from vertexai.generative_models import GenerativeModel

# TODO(developer): Update and un-comment below line
# project_id = "PROJECT_ID"

vertexai.init(project=project_id, location="us-central1")

model = GenerativeModel(model_name="gemini-1.5-flash-001")

response = model.generate_content(
    "What's a good name for a flower shop that specializes in selling bouquets of dried flowers?"
)

print(response.text)

#sh

Guía de inicio rápido: Envía solicitudes a la API de Vertex AI para Gemini | Generative AI on Vertex AI | Google Cloud

@Spsypg

pip3 install "google-cloud-aiplatform>=1.38"

#sh

Guía de inicio rápido: Envía solicitudes a la API de Vertex AI para Gemini | Generative AI on Vertex AI | Google Cloud

@Spsypg

gcloud auth application-default login

Online Python Compiler (Interpreter)

@Ethan123

https://www.programiz.com/python-programming/online-compiler/

TextDemo.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.event.*;

public class TextDemo implements ActionListener 

{ 

    private JFrame frame;

	private JTextField tf1, tf2, tf3;

	private JTextArea ta;

	private JLabel label, label2;

	private JButton b;

		

	public TextDemo()

	{

		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		 

		frame.setLayout(new FlowLayout());	

		

		tf1 = new JTextField("Enter the name", 25); tf2 = new JTextField(20); tf3 = new JTextField("Enter a value");

		tf1.setFont(new Font("Verdana", Font.BOLD, 18));

		tf2.setFont(new Font("Verdana", Font.BOLD, 18));

		tf3.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(tf1); frame.add(tf2); frame.add(tf3);

		//tf1.addActionListener(this); tf2.addActionListener(this); tf3.addActionListener(this);

		

		ta = new JTextArea(20, 15);

		ta.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(ta);

				

		label = new JLabel();

		label.setFont(new Font("Verdana", Font.BOLD, 18));

		label.setForeground(Color.RED);

		frame.add(label);

		

		label2 = new JLabel();

		label2.setFont(new Font("Verdana", Font.BOLD, 18));

		label2.setForeground(Color.green);

		frame.add(label2);

		

		b = new JButton("Display");

		b.addActionListener(this);

		frame.add(b);

		

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

		public void actionPerformed(ActionEvent ae)

	{   String message ="";

		message += tf1.getText()+": ";

		message += tf2.getText()+": ";

		message += tf3.getText()+": ";

		label.setText(message);

		label2.setText(ta.getText());

	}

		

	public static void main(String[] args)

	{   new TextDemo();

	}

}

ListDemo.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.event.*;

public class ListDemo implements ListSelectionListener

{ 

    private JFrame frame;

	private JList<String> list;

	private JLabel label;

	private JToolTip tip;

		public ListDemo()

	{

		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		 

		frame.setLayout(new FlowLayout());	

		

		String[] months = {"January", "February", "March", "April", "May", "June", "July", "August", 

		                   "September", "October", "November", "December"};

		list = new JList<String>(months);

		list.addListSelectionListener(this);

		frame.add(list);

		

		//JScrollPane sp = new JScrollPane(list);

		//frame.add(sp);

		

		label = new JLabel("I show the selected Date");

		label.setFont(new Font("Verdana", Font.BOLD, 18));

		label.setForeground(Color.RED);

		frame.add(label);

		

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

	

	public void valueChanged(ListSelectionEvent ae)

	{   String message = "";

	    for(String each: list.getSelectedValuesList())

			message += each +" ";

		label.setText(message);		 

	}

	

	public static void main(String[] args)

	{   new ListDemo();

	}

}

ComboBoxDemo2.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class ComboBoxDemo2 implements ActionListener

{ 

    private JFrame frame;

	private JComboBox cb1, cb2, cb3;

	private JLabel label;

		public ComboBoxDemo2()

	{

		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		 

		frame.setLayout(new FlowLayout());	

		

		String[] months = {"January", "February", "March", "April", "May", "June", "July", "August", 

		                   "September", "October", "November", "December"};

		cb1 = new JComboBox(); cb2 = new JComboBox(months); cb3 = new JComboBox();

		

		for(int i = 1; i<=31; i++){ cb1.addItem(i); }

		for(int i = 1970; i<2048; i++){ cb3.addItem(i); }	

				

		cb1.addActionListener(this); cb2.addActionListener(this); cb3.addActionListener(this);

		frame.add(cb1); frame.add(cb2); frame.add(cb3);

		

		label = new JLabel("I show the selected Date");

		label.setFont(new Font("Verdana", Font.BOLD, 18));

		label.setForeground(Color.RED);

		frame.add(label);

				

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

	

	public void actionPerformed(ActionEvent ae)

	{   String message = "";

	    message += (Integer)cb1.getSelectedItem()+", ";

		message += (String)cb2.getSelectedItem()+", ";

		message += (Integer)cb3.getSelectedItem();

		label.setText(message);		 

	}

	

	public static void main(String[] args)

	{   new ComboBoxDemo2();

	}

}

ComboBoxDemo.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class ComboBoxDemo implements ActionListener

{ 

    private JFrame frame;

	private JComboBox cb;

	private JLabel label;

		

	public ComboBoxDemo()

	{

		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		 

		frame.setLayout(new FlowLayout());	

		

		cb = new JComboBox();

		cb.addItem("Banana"); cb.addItem("Apple"); cb.addItem("Orange"); 

		cb.addItem("Grape");  cb.addItem("Mango"); cb.addItem("Pineapple");			

		

		cb.addActionListener(this);

		frame.add(cb);

		

		label = new JLabel("I show the selected item");

		label.setFont(new Font("Verdana", Font.BOLD, 18));

		label.setForeground(Color.RED);

		frame.add(label);

				

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

		public void actionPerformed(ActionEvent ae)

	{   label.setText((String)cb.getSelectedItem());		 

	}

	

	public static void main(String[] args)

	{   new ComboBoxDemo();

	}

}

RadioButtonDemo.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class RadioButtonDemo implements ActionListener

{ 

    private JFrame frame;

	private JRadioButton c1, c2, c3, c4;

	private JLabel label;

	 

	public RadioButtonDemo()

	{

		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		 

		frame.setLayout(new FlowLayout());	

		

		c1 = new JRadioButton("Pizza");

		c1.addActionListener(this);

		c1.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c1);

		

		c2 = new JRadioButton("Burger");

		c2.addActionListener(this);

		c2.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c2);

		

		c3 = new JRadioButton("Rolls");

		c3.addActionListener(this);

		c3.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c3);

		

		c4 = new JRadioButton("Beverage");

		c4.addActionListener(this);

		c4.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c4);

		

		ButtonGroup bg = new ButtonGroup();

		bg.add(c1); bg.add(c2); bg.add(c3); bg.add(c4);

		

		label = new JLabel("I show the selected items");

		label.setFont(new Font("Verdana", Font.BOLD, 18));

		label.setForeground(Color.RED);

		frame.add(label);

				

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

		public void actionPerformed(ActionEvent ae)

	{   label.setText(ae.getActionCommand());		 

	}

	

	public static void main(String[] args)

	{   new RadioButtonDemo();

	}

}

#javascript

create a `a` element using react.dom

@deepakm__

var link = React.DOM.a({
                    href: this.makeHref('login')
                },
                'log in'
            );// or React.createElement or
//var link = <a href={this.makeHref('login')}>
//   'log in'</a>;
<div>{'Please '+ link + ' with your email...'}</div>

CheckBoxDemo.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class CheckBoxDemo implements ItemListener

{ 

private JFrame frame;

	private JCheckBox c1, c2, c3, c4;

	private JLabel label;

	private String message =" ";

		public CheckBoxDemo()

	{

		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		 

		frame.setLayout(new FlowLayout());	

		

		c1 = new JCheckBox("Pizza");

		c1.addItemListener(this);

		c1.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c1);

		

		c2 = new JCheckBox("Burger");

		c2.addItemListener(this);

		c2.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c2);

		

		c3 = new JCheckBox("Rolls");

		c3.addItemListener(this);

		c3.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c3);

		

		c4 = new JCheckBox("Beverage");

		c4.addItemListener(this);

		c4.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(c4);

		

		label = new JLabel("I show the selected items");

		label.setFont(new Font("Verdana", Font.BOLD, 18));

		label.setForeground(Color.RED);

		frame.add(label);

		

		

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

	

	public void itemStateChanged(ItemEvent ie)

	{

		if(c1.isSelected())

			message += c1.getText() +" ";

		if(c2.isSelected())

			message += c2.getText() +" ";

		if(c3.isSelected())

			message += c3.getText() +" ";

		if(c4.isSelected())

			message += c4.getText() +" ";

		label.setText(message);

		

		message = " ";

	}

	

	public static void main(String[] args)

	{

		new CheckBoxDemo();

	}

}

ButtonDemo.java

@projectrock

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class ButtonDemo  

{   private JFrame frame;

    private JLabel label;

	private JButton b1, b2; 

		public ButtonDemo()

	{

		frame = new JFrame("A Simple Swing App");

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		

		frame.setLayout(new FlowLayout());	

		

		label = new JLabel("I show the button text");

		label.setFont(new Font("Verdana", Font.BOLD, 18));	

		frame.add(label);

		

		b1 = new JButton("The First Button");

		b1.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(b1);

		b1.addActionListener(new ActionListener(){

			public void actionPerformed(ActionEvent ae)

			{   label.setText(b1.getText()+" is pressed!"); 	}

		});

		

		b2 = new JButton("The Second Button");

		b2.setFont(new Font("Verdana", Font.BOLD, 18));

		frame.add(b2);

		b2.addActionListener(new ActionListener(){

			public void actionPerformed(ActionEvent ae)

			{   label.setText(b2.getText()+" is pressed!"); 	}

		});

				

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

	

	public static void main(String[] args)

	{   new ButtonDemo();

	}

}

LabelDemo.java

@projectrock


import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class LabelDemo

{   private JFrame frame;

    private JLabel label;

	 

	public LabelDemo()

	{

		frame = new JFrame("A Simple Swing App");

		Toolkit tk = frame.getToolkit();

		Dimension dim = tk.getScreenSize();

		int width = (int)dim.getWidth();

		int height = (int)dim.getHeight();

		frame.setSize(width, height);

		

		frame.setLayout(new FlowLayout());	

		

		ImageIcon ic = new ImageIcon("Animated_butterfly.gif");

		

		label = new JLabel("A Butterfly", ic, JLabel.CENTER);

		label.setFont(new Font("Verdana", Font.BOLD, 18));	

		label.setBackground(Color.yellow);

		frame.add(label);

				

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

		public static void main(String[] args)

	{   new LabelDemo();

	}

}

chatGPT prompt for editing

@miskat80

When preparing an interview for publication, please ensure the following types of content are edited out to maintain political correctness, inclusivity, and to avoid legal issues:

Offensive language, including profanity and derogatory terms.
Discriminatory remarks based on race, gender, sexuality, or other protected characteristics.
Unsubstantiated claims or potentially libelous statements.
Personal attacks or defamatory comments about individuals or organizations.
Confidential or sensitive information that breaches privacy laws.
Strong political opinions or endorsements that are not relevant to the publication.
Inappropriate jokes or comments that could be perceived as insensitive.
Negative comments about competitors or other professionals in the field.
Inflammatory statements that could incite violence or public outrage.
Unprofessional comments that reflect poorly on the interviewee or the publication.
Any content that could lead to legal action, such as defamatory statements or breaches of confidentiality.
Misleading information or factually incorrect statements.
Excessive self-promotion that detracts from the informative nature of the interview.
Ambiguous statements that are unclear or open to misinterpretation.
Sensitive cultural references that could be seen as disrespectful.
Please review and edit the interview content carefully to ensure it adheres to these guidelines.

This prompt can help journalists ensure their interviews are polished and safe for publication.

#java

35) TEXT DEMO

@varuntej

TextDemo.java

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

public class TextDemo implements ActionListener
{
    private JFrame frame;
	private JTextField tf1, tf2, tf3;
	private JTextArea ta;
	private JLabel label, label2;
	private JButton b;

	public TextDemo()
	{
		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);
		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		tf1 = new JTextField("Enter the name", 25); tf2 = new JTextField(20); tf3 = new JTextField("Enter a value");
		tf1.setFont(new Font("Verdana", Font.BOLD, 18));
		tf2.setFont(new Font("Verdana", Font.BOLD, 18));
		tf3.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(tf1); frame.add(tf2); frame.add(tf3);
		//tf1.addActionListener(this); tf2.addActionListener(this); tf3.addActionListener(this);

		ta = new JTextArea(20, 15);
		ta.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(ta);

		label = new JLabel();
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setForeground(Color.RED);
		frame.add(label);

		label2 = new JLabel();
		label2.setFont(new Font("Verdana", Font.BOLD, 18));
		label2.setForeground(Color.green);
		frame.add(label2);

		b = new JButton("Display");
		b.addActionListener(this);
		frame.add(b);

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public void actionPerformed(ActionEvent ae)
	{   String message ="";
		message += tf1.getText()+": ";
		message += tf2.getText()+": ";
		message += tf3.getText()+": ";
		label.setText(message);
		label2.setText(ta.getText());
	}

	public static void main(String[] args)
	{   new TextDemo();
	}
}

#java

34) LIST DEMO

@varuntej

ListDemo.java

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

public class ListDemo implements ListSelectionListener
{
    private JFrame frame;
	private JList<String> list;
	private JLabel label;
	private JToolTip tip;

	public ListDemo()
	{
		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);
		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		String[] months = {"January", "February", "March", "April", "May", "June", "July", "August",
		                   "September", "October", "November", "December"};
		list = new JList<String>(months);
		list.addListSelectionListener(this);
		frame.add(list);

		//JScrollPane sp = new JScrollPane(list);
		//frame.add(sp);

		label = new JLabel("I show the selected Date");
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setForeground(Color.RED);
		frame.add(label);

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public void valueChanged(ListSelectionEvent ae)
	{   String message = "";
	    for(String each: list.getSelectedValuesList())
			message += each +" ";
		label.setText(message);
	}

	public static void main(String[] args)
	{   new ListDemo();
	}
}

#java

33) COMBO BOX DEMO 2

@varuntej

ComboBoxDemo2.java

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

public class ComboBoxDemo2 implements ActionListener
{
    private JFrame frame;
	private JComboBox cb1, cb2, cb3;
	private JLabel label;

	public ComboBoxDemo2()
	{
		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);
		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		String[] months = {"January", "February", "March", "April", "May", "June", "July", "August",
		                   "September", "October", "November", "December"};
		cb1 = new JComboBox(); cb2 = new JComboBox(months); cb3 = new JComboBox();

		for(int i = 1; i<=31; i++){ cb1.addItem(i); }
		for(int i = 1970; i<2048; i++){ cb3.addItem(i); }

		cb1.addActionListener(this); cb2.addActionListener(this); cb3.addActionListener(this);
		frame.add(cb1); frame.add(cb2); frame.add(cb3);

		label = new JLabel("I show the selected Date");
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setForeground(Color.RED);
		frame.add(label);

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public void actionPerformed(ActionEvent ae)
	{   String message = "";
	    message += (Integer)cb1.getSelectedItem()+", ";
		message += (String)cb2.getSelectedItem()+", ";
		message += (Integer)cb3.getSelectedItem();
		label.setText(message);
	}

	public static void main(String[] args)
	{   new ComboBoxDemo2();
	}
}

#java

32) COMBO BOX DEMO 1

@varuntej

ComboBoxDemo.java

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

public class ComboBoxDemo implements ActionListener
{
    private JFrame frame;
	private JComboBox cb;
	private JLabel label;

	public ComboBoxDemo()
	{
		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);
		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		cb = new JComboBox();
		cb.addItem("Banana"); cb.addItem("Apple"); cb.addItem("Orange");
		cb.addItem("Grape");  cb.addItem("Mango"); cb.addItem("Pineapple");

		cb.addActionListener(this);
		frame.add(cb);

		label = new JLabel("I show the selected item");
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setForeground(Color.RED);
		frame.add(label);

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public void actionPerformed(ActionEvent ae)
	{   label.setText((String)cb.getSelectedItem());
	}

	public static void main(String[] args)
	{   new ComboBoxDemo();
	}
}

#java

31) RADIO BUTTON DEMO

@varuntej

RadioButtonDemo.java

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

public class RadioButtonDemo implements ActionListener
{
    private JFrame frame;
	private JRadioButton c1, c2, c3, c4;
	private JLabel label;

	public RadioButtonDemo()
	{
		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);
		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		c1 = new JRadioButton("Pizza");
		c1.addActionListener(this);
		c1.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c1);

		c2 = new JRadioButton("Burger");
		c2.addActionListener(this);
		c2.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c2);

		c3 = new JRadioButton("Rolls");
		c3.addActionListener(this);
		c3.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c3);

		c4 = new JRadioButton("Beverage");
		c4.addActionListener(this);
		c4.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c4);

		ButtonGroup bg = new ButtonGroup();
		bg.add(c1); bg.add(c2); bg.add(c3); bg.add(c4);

		label = new JLabel("I show the selected items");
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setForeground(Color.RED);
		frame.add(label);

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public void actionPerformed(ActionEvent ae)
	{   label.setText(ae.getActionCommand());
	}

	public static void main(String[] args)
	{   new RadioButtonDemo();
	}
}

#java

30) CHECK BOX DEMO

@varuntej

CheckBoxDemo.java

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

public class CheckBoxDemo implements ItemListener
{
private JFrame frame;
	private JCheckBox c1, c2, c3, c4;
	private JLabel label;
	private String message =" ";

	public CheckBoxDemo()
	{
		frame = new JFrame("A Simple Swing App");

		//frame.setSize(600, 400);
		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		c1 = new JCheckBox("Pizza");
		c1.addItemListener(this);
		c1.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c1);

		c2 = new JCheckBox("Burger");
		c2.addItemListener(this);
		c2.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c2);

		c3 = new JCheckBox("Rolls");
		c3.addItemListener(this);
		c3.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c3);

		c4 = new JCheckBox("Beverage");
		c4.addItemListener(this);
		c4.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(c4);

		label = new JLabel("I show the selected items");
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setForeground(Color.RED);
		frame.add(label);


		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public void itemStateChanged(ItemEvent ie)
	{
		if(c1.isSelected())
			message += c1.getText() +" ";
		if(c2.isSelected())
			message += c2.getText() +" ";
		if(c3.isSelected())
			message += c3.getText() +" ";
		if(c4.isSelected())
			message += c4.getText() +" ";
		label.setText(message);

		message = " ";
	}

	public static void main(String[] args)
	{
		new CheckBoxDemo();
	}
}

#java

29) BUTTON DEMO

@varuntej

ButtonDemo.java

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

public class ButtonDemo  
{   private JFrame frame;
    private JLabel label;
	private JButton b1, b2;

	public ButtonDemo()
	{
		frame = new JFrame("A Simple Swing App");

		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		label = new JLabel("I show the button text");
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(label);

		b1 = new JButton("The First Button");
		b1.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(b1);
		b1.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent ae)
			{   label.setText(b1.getText()+" is pressed!"); 	}
		});

		b2 = new JButton("The Second Button");
		b2.setFont(new Font("Verdana", Font.BOLD, 18));
		frame.add(b2);
		b2.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent ae)
			{   label.setText(b2.getText()+" is pressed!"); 	}
		});

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public static void main(String[] args)
	{   new ButtonDemo();
	}
}

#java

28) LABEL DEMO

@varuntej

LabelDemo.java

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

public class LabelDemo
{   private JFrame frame;
    private JLabel label;

	public LabelDemo()
	{
		frame = new JFrame("A Simple Swing App");

		Toolkit tk = frame.getToolkit();
		Dimension dim = tk.getScreenSize();
		int width = (int)dim.getWidth();
		int height = (int)dim.getHeight();
		frame.setSize(width, height);

		frame.setLayout(new FlowLayout());

		ImageIcon ic = new ImageIcon("Animated_butterfly.gif");

		label = new JLabel("A Butterfly", ic, JLabel.CENTER);
		label.setFont(new Font("Verdana", Font.BOLD, 18));
		label.setBackground(Color.yellow);
		frame.add(label);

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}

	public static void main(String[] args)
	{   new LabelDemo();
	}
}

#java

27)Write a program to synchronize threads. Use Producer and Consumer problem to illustrate the concept.

@varuntej

import java.util.LinkedList;

class SharedResource {
    private LinkedList buffer = new LinkedList<>();
    private int capacity = 2;

    public void produce() throws InterruptedException {
        synchronized (this) {
            while (buffer.size() == capacity) {
                wait();
            }

            int item = (int) (Math.random() * 100);
            System.out.println("Produced: " + item);
            buffer.add(item);

            notify();
        }
    }

    public void consume() throws InterruptedException {
        synchronized (this) {
            while (buffer.isEmpty()) {
                wait();
            }

            int item = buffer.removeFirst();
            System.out.println("Consumed: " + item);

            notify();
        }
    }
}

class Producer extends Thread {
    private SharedResource sharedResource;

    public Producer(SharedResource sharedResource) {
        this.sharedResource = sharedResource;
    }

    @Override
    public void run() {
        try {
            while (true) {
                sharedResource.produce();
                Thread.sleep(1000);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

class Consumer extends Thread {
    private SharedResource sharedResource;

    public Consumer(SharedResource sharedResource) {
        this.sharedResource = sharedResource;
    }

    @Override
    public void run() {
        try {
            while (true) {
                sharedResource.consume();
                Thread.sleep(1000);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class ProducerConsumerExample {
    public static void main(String[] args) {
        SharedResource sharedResource = new SharedResource();

        Producer producer = new Producer(sharedResource);
        Consumer consumer = new Consumer(sharedResource);

        producer.start();
        consumer.start();
    }
}

#java

26)Write a program to show the assignment of thread priorities.

@varuntej

class MyThread extends Thread {
    public void run() {
        System.out.println("run method");
        System.out.println("run method priority: " + Thread.currentThread().getPriority());
        Thread.currentThread().setPriority(4);
        System.out.println("run method priority after setting: " + Thread.currentThread().getPriority());
    }

    public static void main(String[] args) {
        System.out.println("main method");
        System.out.println("main method priority before setting: " + Thread.currentThread().getPriority());

        Thread.currentThread().setPriority(9);

        System.out.println("main method priority after setting: " + Thread.currentThread().getPriority());
    }
}

#java

25)Write programs to illustrate the use of Thread class and Runnable interface.

@varuntej

class MyThread implements Runnable {

    public void run() {
        System.out.println("Hello");
        System.out.println("DS");
    }

    public static void main(String[] args) {
        MyThread obj = new MyThread();
        Thread t = new Thread(obj);
        t.start();
    }
}

#java

24) Demonstrate assertions through simple programs.

@varuntej

public class AssertionExample {
    public static void main(String[] args) {
        int age = 26;

        // simple assertion to check if age is greater than or equal to 18
        assert age >= 18 : "Age must be 18 or older";

        // Rest of the program
        System.out.println("Program continues after the assertion check");

        // More code...
    }
}

#java

23)Write a program to demonstrate enumerations and usage of Assertions.

@varuntej

public class SeasonExample {
    public enum Season {
        WINTER, SPRING, SUMMER, FALL;
    }

    public static void main(String[] args) {
        int x = 26;

        for (Season s : Season.values()) {
            System.out.println(s);
        }

        assert x == 26 : "Assertion failed"; // Assert that x is 26

        System.out.println(x);
    }
}

#java

22)Use the classes StringTokenizer, StringReader and StringWriter to write a program to find the capabilities of these classes.

@varuntej

import java.util.StringTokenizer;
import java.io.StringReader;
import java.io.StringWriter;

public class StringExample {
    public static void main(String[] args) {
        try {
            StringTokenizer st = new StringTokenizer("My name is Raj");

            while (st.hasMoreTokens()) {
                System.out.println(st.nextToken());
            }

            String s = "Hello World";

            StringReader reader = new StringReader(s);
            int k = 0;

            while ((k = reader.read()) != -1) {
                System.out.print((char) k + ", ");
            }

            System.out.println("\nIn Data is the StringWriter: " + s);

            StringWriter output = new StringWriter();
            output.write(s);

            System.out.println("In Data is the StringWriter: " + output.toString());

            output.close();
        } catch (Exception e) {
            System.out.println("Exception: " + e.getMessage());
        }
    }
}

#java

21)Write a Java Program that displays the number of characters, lines and words in a text file.

@varuntej

import java.io.*;

class Test {
    public static void main(String args[]) {
        String path = "sample.txt";
        try {
            BufferedReader br = new BufferedReader(new FileReader(path));
            int charCount = 0;
            int lineCount = 0;
            int wordCount = 0;
            String line;

            while ((line = br.readLine()) != null) {
                charCount += line.length();
                lineCount++;
                String[] words = line.split("\\s+");
                wordCount += words.length;
            }

            br.close();

            System.out.println("Number of characters: " + charCount);
            System.out.println("Number of words: " + wordCount);
            System.out.println("Number of lines: " + lineCount);
        } catch (IOException e) {
            System.out.println(e);
        }
    }
}

#java

20)Using FileReader and FileWriter, write a program to perform file copying and any other suitable operations.

@varuntej

import java.io.*;

public class FileCopyExample {

    public static void main(String[] args) {
        try {
            FileReader fr1 = new FileReader("source.txt");
            FileWriter fw2 = new FileWriter("destination.txt");

            int i;
            while ((i = fr1.read()) != -1) {
                fw2.write((char) i);
            }

            System.out.println("File copied");

            fr1.close();
            fw2.close();
        } catch (IOException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

#java

19)Using byte streams, write a program to both read from and write to files.

@varuntej

import java.io.*;

public class FileExample {
    static FileInputStream fis;

    public static void main(String[] args) {
        try {
            fis = new FileInputStream("example.txt");

            int data;
            while ((data = fis.read()) != -1) {
                System.out.print((char) data);
            }

            fis.close();
        } catch (IOException io) {
            System.out.println("Caught IOException: " + io.getMessage());
        }
    }
}

#java

18)Learn how to create and use custom exceptions.

@varuntej

// Custom exception class
class NegativeNumberException extends Exception {
    public NegativeNumberException(String message) {
        super(message);
    }
}

// Class using the custom exception
public class CustomExceptionExample {
    public static void main(String[] args) {
        try {
            int result = calculateSquare(5);
            System.out.println("Square: " + result);

            result = calculateSquare(-3); // This will throw NegativeNumberException
            System.out.println("Square: " + result); // This line won't be executed
        } catch (NegativeNumberException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }

    // Method that may throw the custom exception
    private static int calculateSquare(int number) throws NegativeNumberException {
        if (number < 0) {
            // Throw the custom exception if the number is negative
            throw new NegativeNumberException("Negative numbers are not allowed.");
        }
        return number * number;
    }
}

#java

17)Write a program to demonstrate the usage of try and associated keywords. Introduce bugs into the program to raise exceptions and then catch and process them.

@varuntej

public class ExceptionExample {
    public static void main(String[] args) {
        int n = 26;
        try {
            int m = n / 0;
        } catch (ArithmeticException e) {
            System.out.println("Exception caught: " + e);
        } finally {
            System.out.println("Any number cannot be divided by zero");
        }
    }
}

#java

16)Write programs using StringBuffer and StringBuilder library classes.

@varuntej

public class StringBufferStringBuilderExample{
public static void main(String args[]){
StringBuffer stringBuffer=new StringBuffer("hello");
stringBuffer.append(" ").append("world");
System.out.println("StringBuffer result:" + stringBuffer);
StringBuilder stringBuilder=new StringBuilder();
stringBuilder.append("is").append("awesome");
System.out.println("StringBuilder result:" + stringBuilder);
}
}

#java

15)Write a program to understand the full capability of String class.Implement as many methods as required. Consult API documentation to read through the methods.

@varuntej

public class StringExample {
    public static void main(String[] args) {
        String s = "Hello World!";
        System.out.println("Original string: " + s);
        System.out.println("Length: " + s.length());
        System.out.println("Uppercase: " + s.toUpperCase());
        System.out.println("Lowercase: " + s.toLowerCase());
        System.out.println("Substring from index 7: " + s.substring(7));
        System.out.println("Replace 'o' with 'x': " + s.replace('o', 'x'));
        System.out.println("Contains 'world': " + s.contains("world"));
        System.out.println("Starts with 'Hello': " + s.startsWith("Hello"));
        System.out.println("Index of 'o': " + s.indexOf('o'));
        System.out.println("Last index of 'o': " + s.lastIndexOf('o'));
        System.out.println("Ends with 'ld!': " + s.endsWith("ld!"));
        System.out.println("Character at index 4: " + s.charAt(4));
        System.out.println("Trimmed: " + s.trim());
    }
}

#java

14)Write a program to demonstrate the usage of interfaces.

@varuntej

// Interface
interface Printable {
    void print();
}

// Class implementing the interface
class Printer implements Printable {
    @Override
    public void print() {
        System.out.println("Printing...");
    }
}

public class InterfaceExample {
    public static void main(String[] args) {
        // Creating an instance of the class implementing the interface
        Printable printer = new Printer();

        // Using the interface method
        printer.print();
    }
}

#java

13)Demonstrate the use of abstract classes. Write a Person abstract class and then subclass that into Student and Faculty classes. Use appropriate fields and methods.

@varuntej

// Abstract class: Person
abstract class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public abstract void displayDetails();

    public void greet() {
        System.out.println("Hello, I am " + name + ".");
    }
}

// Subclass: Student
class Student extends Person {
    private int studentId;

    public Student(String name, int age, int studentId) {
        super(name, age);
        this.studentId = studentId;
    }

    @Override
    public void displayDetails() {
        System.out.println("Student - Name: " + super.getName() + ", Age: " + super.getAge() +
                ", Student ID: " + studentId);
    }

    public void study() {
        System.out.println("Student is studying.");
    }
}

// Subclass: Faculty
class Faculty extends Person {
    private String department;

    public Faculty(String name, int age, String department) {
        super(name, age);
        this.department = department;
    }

    @Override
    public void displayDetails() {
        System.out.println("Faculty - Name: " + super.getName() + ", Age: " + super.getAge() +
                ", Department: " + department);
    }

    public void teach() {
        System.out.println("Faculty is teaching.");
    }
}

public class PersonExample {
    public static void main(String[] args) {
        Student student = new Student("John", 20, 123);
        Faculty faculty = new Faculty("Dr. Smith", 35, "Computer Science");

        student.displayDetails();
        student.greet();
        student.study();

        System.out.println();

        faculty.displayDetails();
        faculty.greet();
        faculty.teach();
    }
}

#java

12)Develop an application that uses inheritance. Use the class Account and then subclass it into different account types. Then making use of Customer and Employee classes to develop the application to reflect the nature of banking operations. Use minimum operational sequence.

@varuntej

// Account class (Base class)
class Account {
 private int accountNumber;
 private double balance;
 public Account(int accountNumber) {
 this.accountNumber = accountNumber;
 this.balance = 0.0;
 }
 public int getAccountNumber() {
 return accountNumber;
 }
 public double getBalance() {
 return balance;
 }
 public void deposit(double amount) {
 balance += amount;
 System.out.println("Deposited: $" + amount);
 }
 public void withdraw(double amount) {
 if (amount <= balance) {
 balance -= amount;
 System.out.println("Withdrawn: $" + amount);
 } else {
 System.out.println("Insufficient balance");
 }
 }
}
// Subclasses of Account
class SavingsAccount extends Account {
 // Additional features specific to savings account
 public SavingsAccount(int accountNumber) {
 super(accountNumber);
 }
}
class CheckingAccount extends Account {
 // Additional features specific to checking account
 public CheckingAccount(int accountNumber) {
 super(accountNumber);
 }
}
// Customer class
class Customer {
 private String name;
 private Account account;
 public Customer(String name, Account account) {
 this.name = name;
 this.account = account;
 }
 public void deposit(double amount) {
 account.deposit(amount);
 }
 public void withdraw(double amount) {
 account.withdraw(amount);
 }
 public double checkBalance() {
 return account.getBalance();
 }
}
// Employee class
class Employee {
 private String name;
 public Employee(String name) {
 this.name = name;
 }
 public void processTransaction(Customer customer, double amount,
String type) {
 if (type.equalsIgnoreCase("Deposit")) {
 customer.deposit(amount);
 } else if (type.equalsIgnoreCase("Withdraw")) {
 customer.withdraw(amount);
 } else {
 System.out.println("Invalid transaction type");
 }
 }
}
// Main class for testing
public class BankingApplication {
 public static void main(String[] args) {
 // Create accounts for customers
 SavingsAccount savingsAccount = new SavingsAccount(1001);
 CheckingAccount checkingAccount = new CheckingAccount(2001);
 // Create customers and link accounts
 Customer customer1 = new Customer("Alice", savingsAccount);
 Customer customer2 = new Customer("Bob", checkingAccount);
 // Create bank employees
 Employee employee1 = new Employee("Eve");
 // Employee processing transactions for customers
 employee1.processTransaction(customer1, 1000, "Deposit");
 employee1.processTransaction(customer2, 500, "Withdraw");
 // Checking customer balances after transactions
 System.out.println("Customer 1 Balance: $" +
customer1.checkBalance());
 System.out.println("Customer 2 Balance: $" +
customer2.checkBalance());
 }
}

#java

11))Write a program to understand polymorphic invocation of methods,while overriding the methods. Use an employee base class and manager sub class; override the computeSalary() method to illustrate the concept.

@varuntej

class Employee {
    private String name;
    private double baseSalary;

    public Employee(String name, double baseSalary) {
        this.name = name;
        this.baseSalary = baseSalary;
    }

    public String getName() {
        return name;
    }

    // Base implementation of computeSalary method
    public double computeSalary() {
        return baseSalary;
    }
}
class Manager extends Employee {
    private double bonus;

    public Manager(String name, double baseSalary, double bonus) {
        super(name, baseSalary);
        this.bonus = bonus;
    }

    // Override computeSalary method to include bonus
    @Override
    public double computeSalary() {
        // Calling the base class method using super
        double baseSalary = super.computeSalary();
        return baseSalary + bonus;
    }
}
public class PolymorphicInvocationExample {
    public static void main(String[] args) {
        // Polymorphic invocation using base class reference
        Employee emp1 = new Employee("John Doe", 50000.0);
        System.out.println("Employee Salary: $" + emp1.computeSalary());

        // Polymorphic invocation using subclass reference
        Employee emp2 = new Manager("Jane Smith", 60000.0, 10000.0);
        System.out.println("Manager Salary: $" + emp2.computeSalary());
    }
}

#java

10)write a program using the hierarchy of employees in a university

@varuntej

// Employee class (base class)
class Employee {
    private String name;
    private int employeeId;

    public Employee(String name, int employeeId) {
        this.name = name;
        this.employeeId = employeeId;
    }

    public String getName() {
        return name;
    }

    public int getEmployeeId() {
        return employeeId;
    }

    public void displayDetails() {
        System.out.println("Employee ID: " + employeeId);
        System.out.println("Name: " + name);
    }
}

// Faculty class (inherits from Employee)
class Faculty extends Employee {
    private String department;
    private String designation;

    public Faculty(String name, int employeeId, String department, String designation) {
        super(name, employeeId);
        this.department = department;
        this.designation = designation;
    }

    public String getDepartment() {
        return department;
    }

    public String getDesignation() {
        return designation;
    }

    @Override
    public void displayDetails() {
        super.displayDetails();
        System.out.println("Department: " + department);
        System.out.println("Designation: " + designation);
    }
}

// Staff class (inherits from Employee)
class Staff extends Employee {
    private String role;

    public Staff(String name, int employeeId, String role) {
        super(name, employeeId);
        this.role = role;
    }

    public String getRole() {
        return role;
    }

    @Override
    public void displayDetails() {
        super.displayDetails();
        System.out.println("Role: " + role);
    }
}

// UniversityProgram class (main program)
public class UniversityProgram {
    public static void main(String[] args) {
        // Creating instances of Faculty and Staff
        Faculty facultyMember = new Faculty("John Doe", 101, "Computer Science", "Professor");
        Staff staffMember = new Staff("Jane Smith", 201, "Administrative Assistant");

        // Displaying details of Faculty and Staff
        System.out.println("Faculty Details:");
        facultyMember.displayDetails();
        System.out.println();

        System.out.println("Staff Details:");
        staffMember.displayDetails();
    }
}

#java

9))Write a program to use gc() method of both System and Runtime classes. Experiment with other methods of those classes.

@varuntej

public classgc
{
public static void main(String args[])
{
System.gc();
System.out.println("garbage collection is required using system.gc()");
runtime.getruntime().gc();
System.out.println("garbage collection is required using system.gc()");
Sytsem.out.println("free menory:"+runtime.getruntime() freememory()+"bytes");
System.out.println("total memory:"+runtime.getruntime().totalmemory()+"bytes");
System.out.println("available processors"+runtime.getruntime()available processors());
runtime.getruntime().exit(0);
System.out.println("this linewill not be executed");
}
}

#java

8)Write a program to utilize both standard and custom packages. The program should reflect the usage of packages in a correct manner, along with the purpose of access modifiers

@varuntej

package com.example.custom;
import java.util.ArrayList; // Import ArrayList from java.util package
class CustomClass {
void display() {
System.out.println("Custom class in the custom package.");
}
}
public class Main {
public static void main(String args[]) {
ArrayList list = new ArrayList<>(); // Fix the typo in ArrayList declaration
list.add("hello");
list.add("world");
System.out.println("ArrayList from java.util package: " + list);
CustomClass customObj = new CustomClass();
customObj.display();
AccessModifiersDemo demo = new AccessModifiersDemo();
demo.publicMethod();
demo.defaultMethod();
}
}
class AccessModifiersDemo {
public void publicMethod() {
System.out.println("Public method can be accessed from anywhere.");
}
void defaultMethod() {
System.out.println("Default method can be accessed within the same package.");
}
}

#java

7)Practice further programs on the usage of arrays in java

@varuntej

public class ArrayOperations {
    public static void main(String[] args) {
        // Initializing an array
        int[] numbers = { 5, 12, 8, 3, 15 };

        // Accessing elements
        System.out.println("Element at index 2: " + numbers[2]);

        // Finding the length of the array
        System.out.println("Length of the array: " + numbers.length);

        // Modifying an element
        numbers[1] = 20;

        // Printing the array
        System.out.print("Modified array: ");
        for (int i = 0; i < numbers.length; i++) {
            System.out.print(numbers[i] + " ");
        }
        System.out.println();

        // Finding the maximum element
        int maxElement = numbers[0];
        for (int i = 1; i < numbers.length; i++) {
            if (numbers[i] > maxElement) {
                maxElement = numbers[i];
            }
        }
        System.out.println("Maximum element: " + maxElement);

        // Finding the minimum element
        int minElement = numbers[0];
        for (int i = 1; i < numbers.length; i++) {
            if (numbers[i] < minElement) {
                minElement = numbers[i];
            }
        }
        System.out.println("Minimum element: " + minElement);

        // Iterating through the array to calculate the sum
        int sum = 0;
        for (int num : numbers) {
            sum += num;
        }
        System.out.println("Sum of elements: " + sum);
    }
}

#java

6)Use array sum of integers and find the sum and average of the elements of that array in java

@varuntej

public class ArraySumAverage {
    public static void main(String[] args) {
        // Predefined array of integers
        int[] array = { 10, 20, 30, 40, 50 };

        // Calculate sum and average
        int sum = 0;
        for (int i = 0; i < array.length; i++) {
            sum += array[i];
        }
        double average = (double) sum / array.length;

        // Output: Sum and Average
        System.out.println("Sum of the elements: " + sum);
        System.out.println("Average of the elements: " + average);
    }
}

#java

5)type casting task 2B

@varuntej

class Explicit
{
    public static void main(String[] args)
    {
        long l=99;
        int i=(int)l;
        System.out.println("long value ="+l);
        System.out.println("int value ="+i);
    }
}

#java

4)Constructor and method overloading task 2a

@varuntej

##Constructor overloading##

class T
{
    T()
    {
        System.out.println("0-args");
    }
    T(int i)
    {
        System.out.println("1-args");
    }
    T(int i,int j)
    {
        System.out.println("2-args");
    }
    public static void main(String[] args)
    {
        System.out.println("constructor overloading");
        T t1=new T();
        T t2=new T(10);
        T t3=new T(20,30);
    }
}





##Method overloading##

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

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

    public static void main(String[] args) {
        System.out.println(add(11, 11));
    }
}

#java

3)command line arguments 1C

@varuntej

class Comdargs{
public static void main(String[] args){
System.out.println(args[0]+" "+args[1]);
System.out.println(args[0]+args[1]);
}
}


###IN THE COMMAND PROMPT AFTER JAVA COMDARGS GIVE YOUR COMMAND LINE ARRGUMENTS###

#java

2)Student grade task 1B

@varuntej

import java.util.Scanner;

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

        System.out.print("Enter the student's score: ");
        int score = scanner.nextInt();

        char grade = getGradeSwitch(score);

        System.out.println("Grade: " + grade);
    }

    public static char getGradeSwitch(int score) {
        int range = score / 10;

        switch (range) {
            case 10:
            case 9:
                return 'A';
            case 8:
                return 'B';
            case 7:
                return 'C';
            case 6:
                return 'D';
            default:
                return 'F';
        }
    }
}



USING IF -ELSE

import java.util.Scanner;

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

        System.out.print("Enter the student's score: ");
        int score = scanner.nextInt();

        char grade = getGradeIfElse(score);

        System.out.println("Grade: " + grade);
    }

    public static char getGradeIfElse(int score) {
        if (score >= 90 && score <= 100) {
            return 'A';
        } else if (score >= 80 && score < 90) {
            return 'B';
        } else if (score >= 70 && score < 80) {
            return 'C';
        } else if (score >= 60 && score < 70) {
            return 'D';
        } else if (score >= 0 && score < 60) {
            return 'F';
        } else {
            // Handle invalid score (outside the range 0-100)
            System.out.println("Invalid score. Please enter a score between 0 and 100.");
            return '\0'; // '\0' is used to represent an undefined character
        }
    }
}

object oriented programming

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Online Python Compiler (Interpreter)

TextDemo.java

ListDemo.java

ComboBoxDemo2.java

ComboBoxDemo.java

RadioButtonDemo.java

create a `a` element using react.dom

CheckBoxDemo.java

ButtonDemo.java

LabelDemo.java

chatGPT prompt for editing

35) TEXT DEMO

34) LIST DEMO

33) COMBO BOX DEMO 2

32) COMBO BOX DEMO 1

31) RADIO BUTTON DEMO

30) CHECK BOX DEMO

29) BUTTON DEMO

28) LABEL DEMO

27)Write a program to synchronize threads. Use Producer and Consumer problem to illustrate the concept.

26)Write a program to show the assignment of thread priorities.

25)Write programs to illustrate the use of Thread class and Runnable interface.

24) Demonstrate assertions through simple programs.

23)Write a program to demonstrate enumerations and usage of Assertions.

22)Use the classes StringTokenizer, StringReader and StringWriter to write a program to find the capabilities of these classes.

21)Write a Java Program that displays the number of characters, lines and words in a text file.

20)Using FileReader and FileWriter, write a program to perform file copying and any other suitable operations.

19)Using byte streams, write a program to both read from and write to files.

18)Learn how to create and use custom exceptions.

17)Write a program to demonstrate the usage of try and associated keywords. Introduce bugs into the program to raise exceptions and then catch and process them.

16)Write programs using StringBuffer and StringBuilder library classes.

15)Write a program to understand the full capability of String class.Implement as many methods as required. Consult API documentation to read through the methods.

14)Write a program to demonstrate the usage of interfaces.

13)Demonstrate the use of abstract classes. Write a Person abstract class and then subclass that into Student and Faculty classes. Use appropriate fields and methods.

12)Develop an application that uses inheritance. Use the class Account and then subclass it into different account types. Then making use of Customer and Employee classes to develop the application to reflect the nature of banking operations. Use minimum operational sequence.

11))Write a program to understand polymorphic invocation of methods,while overriding the methods. Use an employee base class and manager sub class; override the computeSalary() method to illustrate the concept.

10)write a program using the hierarchy of employees in a university

9))Write a program to use gc() method of both System and Runtime classes. Experiment with other methods of those classes.

8)Write a program to utilize both standard and custom packages. The program should reflect the usage of packages in a correct manner, along with the purpose of access modifiers

7)Practice further programs on the usage of arrays in java

6)Use array sum of integers and find the sum and average of the elements of that array in java

5)type casting task 2B

4)Constructor and method overloading task 2a

3)command line arguments 1C

2)Student grade task 1B

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