Salesforce send admin email for error/success

Simple reference code for sending success/failure email in Salesforce

 public static List<String> toAddresses = new List<String>();  
 /** to cache transaction data and reduce SOQLs  
  */  
 public static List<String> getNotificationEmailAddress() {  
   if( toAddresses == null || toAddresses.size() == 0 ) {  
     Profile sysAdminProfile = [SELECT Id FROM Profile WHERE Name = 'System Administrator' limit 10];  
     List<User> sysAdmins = [SELECT id, Email FROM User WHERE ProfileId = :sysAdminProfile.id];  
     for( User sysAdmin : sysAdmins ) {  
       toAddresses.add ( sysAdmin.Email );  
     }  
   }  
   return toAddresses;  
 }  
 public static void sendMail(String subject, String body, List<String> recipients) {  
   try {  
     Messaging.SingleEmailMessage message = new Messaging.SingleEmailMessage();  
     message.toAddresses = recipients;  
     message.optOutPolicy = 'FILTER';  
     message.subject = subject;  
     message.plainTextBody = body;  
     Messaging.SingleEmailMessage[] messages =  new List<Messaging.SingleEmailMessage> {message};  
     Messaging.SendEmailResult[] results = Messaging.sendEmail(messages);  
     if (results[0].success) {  
       System.debug(LoggingLevel.INFO, 'The email was sent successfully . to ' + recipients + ' subject ' + subject );  
     } else {  
       System.debug(LoggingLevel.ERROR, 'The email failed to send: ' + results[0].errors[0].message + ' to ' + recipients + ' subject ' + subject );  
     }  
   } catch(Exception e) {  
     System.debug(LoggingLevel.ERROR, 'The email failed to send: ' + ' to ' + recipients + ' subject ' + subject + ' body ' + body );  
     System.debug( e.getMessage() + '\n' + e.getStackTraceString() );  
   }  
 }  
 sendMail('test email','test body', new List<String> { 'chintanjshah@gmail.com' } );  
 sendMail('test email 2','test body 2', getNotificationEmailAddress() );