Event Handling in Java

 Event handling in Java refers to the process of responding to user actions or other events that occur during program execution. Java provides a robust event-handling mechanism that allows developers to write code that responds to various events, such as mouse clicks, key presses, window resizing, and more.

In Java, event handling involves three main components:

1. Event sources: These are objects that generate events, such as buttons, text fields, and menus.

2. Event objects: These are instances of classes that represent the events generated by event sources. For example, a MouseEvent object represents a mouse click event.

3. Event listeners: These are objects that receive and handle events. An event listener is registered with an event source to receive events of a particular type.

To handle events in Java, you typically create a class that implements an appropriate listener interface. For example, to handle mouse click events, you would implement the MouseListener interface, which defines methods like mouseClicked(), mousePressed(), and mouseReleased().

Once you have implemented the listener interface, you can register an instance of your listener class with the event source using the addEventListener() method. When the event occurs, the event source invokes the appropriate method in your listener class, which can then respond to the event as needed.

Here is an example of registering an event listener for a button in Java:

java
import java.awt.*; 
import java.awt.event.*;
public class MyButtonListener implements ActionListener 
{ 
public void actionPerformed(ActionEvent e) 
{ 
 System.out.println("Button clicked"); 
 } 
}
public class MyFrame extends Frame 
{
    public MyFrame() 
{ 
Button button = new Button("Click me"); 
 button.addActionListener(new MyButtonListener());
        add(button); 
 } 
}

In this example, we create a button and add an instance of MyButtonListener as an action listener for the button. When the button is clicked, the actionPerformed() method in MyButtonListener is called, which simply prints a message to the console.