content: package com.rahul.notificationmaster;
  
  import android.app.Application;
  import android.app.NotificationChannel;
  import android.app.NotificationManager;
  import android.os.Build;
  
  public class App extends Application {
  
      public static final String CHANNEL_1_ID = "channel1";
      public static final String CHANNEL_2_ID = "channel2";
      public static final String CHANNEL_3_ID = "channel3";
      public static final String CHANNEL_4_ID = "channel4";
      public static final String CHANNEL_5_ID = "channel5";
  
  
  
      @Override
      public void onCreate() {
          super.onCreate();
          CreateNotificationChannels();
      }
  
  
  
      private void CreateNotificationChannels() {
  
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
  
              //Channel 1 Configuration
              NotificationChannel channel1 = new NotificationChannel(CHANNEL_1_ID,
                      "channel 1",NotificationManager.IMPORTANCE_HIGH);
              channel1.setDescription("Test Channel 1");
  
              //Channel 2 Configuration
              NotificationChannel channel2 = new NotificationChannel(CHANNEL_2_ID,
                      "channel 2",NotificationManager.IMPORTANCE_LOW);
              channel2.setDescription("Test Channel 2");
  
              //Channel 3 Configuration
              NotificationChannel channel3 = new NotificationChannel(CHANNEL_3_ID,
                      "channel 3",NotificationManager.IMPORTANCE_DEFAULT);
              channel3.setDescription("Test Channel 3");
  
              //Channel 4 Configuration
              NotificationChannel channel4 = new NotificationChannel(CHANNEL_4_ID,
                      "channel 4",NotificationManager.IMPORTANCE_HIGH);
              channel4.setDescription("Test Channel 4");
  
              //Channel 5 Configuration
              NotificationChannel channel5 = new NotificationChannel(CHANNEL_5_ID,
                      "channel 5",NotificationManager.IMPORTANCE_HIGH);
              channel5.setDescription("Test Channel 5");
  
  
  
  
              NotificationManager manager = getSystemService(NotificationManager.class);
              manager.createNotificationChannel(channel1);
              manager.createNotificationChannel(channel2);
              manager.createNotificationChannel(channel3);
              manager.createNotificationChannel(channel4);
              manager.createNotificationChannel(channel5);
  
          }
  
      }
  }
  