ja4

1. Write a Java program using Runnable interface to blink Text on the frame. [15 M]
2. import javax.swing.;
   import java.awt.;
   import java.awt.event.*;

public class BlinkText implements Runnable {
private JLabel label;
private boolean isBlinking;

public BlinkText(JLabel label) {
    this.label = label;
    isBlinking = true;
}

@Override
public void run() {
    try {
        while (isBlinking) {
            Thread.sleep(1000); // Delay for 1 second
            label.setVisible(!label.isVisible()); // Toggle visibility
        }
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

public void stopBlinking() {
    isBlinking = false;
}

public static void main(String[] args) {
    JFrame frame = new JFrame("Blinking Text");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(300, 200);
    frame.setLayout(new FlowLayout());

    JLabel textLabel = new JLabel("Blinking Text");
    frame.add(textLabel);

    BlinkText blinker = new BlinkText(textLabel);
    Thread blinkThread = new Thread(blinker);
    blinkThread.start();

    JButton stopButton = new JButton("Stop");
    stopButton.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            blinker.stopBlinking();
            stopButton.setEnabled(false);
        }
    });
    frame.add(stopButton);

    frame.setVisible(true);
}

}

2. Write a Java program to store city names and their STD codes using an appropriate
   collection and perform following operations:
   i. Add a new city and its code (No duplicates)
   ii. Remove a city from the collection
   iii. Search for a city name and display the code
   import java.util.HashMap;
   import java.util.Map;

public class CityCodes {
private Map<String, Integer> cityCodes;

public CityCodes() {
    cityCodes = new HashMap<>();
}

public void addCity(String city, int code) {
    cityCodes.put(city, code);
}

public void removeCity(String city) {
    cityCodes.remove(city);
}

public int getCode(String city) {
    return cityCodes.getOrDefault(city, -1);
}

public static void main(String[] args) {
    CityCodes cityCodes = new CityCodes();
    
    // Add cities and their codes
    cityCodes.addCity("New York", 212);
    cityCodes.addCity("Los Angeles", 213);
    cityCodes.addCity("Chicago", 312);
    
    // Remove a city
    cityCodes.removeCity("Chicago");
    
    // Search for a city name and display the code
    String city = "Los Angeles";
    int code = cityCodes.getCode(city);
    if (code != -1) {
        System.out.println("STD Code for " + city + ": " + code);
    } else {
        System.out.println(city + " not found");
    }
}

}