access S3 bucket without access key and secrete key

 https://stackoverflow.com/questions/44062813/aws-s3-upload-without-access-and-secret-key-in-java

AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
              .withCredentials(new InstanceProfileCredentialsProvider(false))
              .build();

https://docs.aws.amazon.com/sdk-for-php/v3/developer-guide/guide_credentials_provider.html
https://stackoverflow.com/questions/52286306/using-ec2-metadata-credentials-in-the-laravel-filesystem

string-concatenation-vs-stringbuilder-vs-string-format-performance

 https://kylewbanks.com/blog/java-string-concatenation-vs-stringbuilder-vs-string-format-performance

public class TestStrings {

    private static final String PROFILE_PICTURE_URL_BASE = "https://cdn.myapp.com/user/";
    private static final String PROFILE_PICTURE_URL_EXTENSION = ".png";
    private static final String PROFILE_PICTURE_URL = "https://cdn.myapp.com/user/%d.png";

    private static final int NUM_ITERATIONS = 1000000;
    
    public static void main(String[] args) {
        int userId;
        long startTime;
        
        // String Concatentation
        startTime = System.currentTimeMillis();
        for (userId = 0; userId < NUM_ITERATIONS; userId ++) {
            String profilePictureUrl = PROFILE_PICTURE_URL_BASE + userId + PROFILE_PICTURE_URL_EXTENSION;
        }
        System.out.println("String Concatentation: " + (System.currentTimeMillis() - startTime) + "ms");
        
        // StringBuilder
        startTime = System.currentTimeMillis();
        for (userId = 0; userId < NUM_ITERATIONS; userId ++) {
            StringBuilder sb = new StringBuilder(PROFILE_PICTURE_URL_BASE);
            sb.append(userId);
            sb.append(PROFILE_PICTURE_URL_EXTENSION);
            
            String profilePictureUrl = sb.toString();
        }
        System.out.println("StringBuilder: " + (System.currentTimeMillis() - startTime) + "ms");
        
        // String.format
        startTime = System.currentTimeMillis();
        for (userId = 0; userId < NUM_ITERATIONS; userId ++) {
            String profilePictureUrl = String.format(PROFILE_PICTURE_URL, userId);
        }
        System.out.println("String.format: " + (System.currentTimeMillis() - startTime) + "ms");
    }
}

Making dynamic query

 https://stackoverflow.com/questions/8549619/mysql-dynamically-build-query-string-in-a-stored-procedure-based-on-logic

CREATE  PROCEDURE `activate_games_pawan`(IN `gameId` INT(20))

BEGIN   

DECLARE whereCondition varchar(200);

CASE WHEN gameId>0 THEN

   SET @whereCondition =CONCAT(" ","sh_games.game_id=",gameId);

  SELECT @whereCondition;

  ELSE

  SET @whereCondition=1;

    SELECT @whereCondition;

  END CASE;

 SET @query=CONCAT("SELECT * FROM sh_games where ", @whereCondition);

  select @query;

PREPARE stmt FROM @query;

EXECUTE stmt;

DEALLOCATE PREPARE stmt;

END

Delete duplicate rows from mysql

  SET SQL_SAFE_UPDATES = 0;

    DELETE t1  FROM sh_learning_material AS t1

INNER JOIN sh_learning_material AS t2 

WHERE 

t1.id<t2.id AND

    t1.company_id = t2.company_id;

Send email with attachment in spring boot

 https://howtodoinjava.com/spring-boot2/send-email-with-attachment/

public void sendMailWithAttachment(String to, String subject, String bodyTextMsg, String fileToAttach) 

{

System.out.println("file loc------------"+fileToAttach);

    MimeMessagePreparator preparator = new MimeMessagePreparator() 

    {

        public void prepare(MimeMessage mimeMessage) throws Exception 

        {

            mimeMessage.setRecipient(Message.RecipientType.TO, new InternetAddress(to));

            mimeMessage.setFrom(new InternetAddress(fromEmailId));

            mimeMessage.setSubject(subject);

            

            Multipart multipartContent= new MimeMultipart();

            MimeBodyPart mimeBodyPart =new MimeBodyPart();

            mimeBodyPart.setText(bodyTextMsg);

            MimeBodyPart mimeBodyPartAttachment =new MimeBodyPart();

            mimeBodyPartAttachment.attachFile(fileToAttach);

            multipartContent.addBodyPart(mimeBodyPart);

            multipartContent.addBodyPart(mimeBodyPartAttachment);

            mimeMessage.setContent(multipartContent,"text/csv; charset=utf-8");

            System.out.println("email send sucessfully");

        }

    };

     

    try {

        mailSender.send(preparator);

        System.out.println("email send sucessfully");

        

    }

    catch (MailException ex) {

        // simply log it and go on...

        System.out.println(ex.getMessage());

    }

}

https://coderanch.com/t/271609/java/Java-Mail-send-Multiple-recipients

Read only collection

 https://javarevisited.blogspot.com/2012/07/create-read-only-list-map-set-example-java.html#axzz6obBnjvcF

Generate and Load SSH Keys into SourceTree with PuTTY

 https://confluence.atlassian.com/sourcetreekb/generate-and-load-ssh-keys-into-sourcetree-with-putty-790629663.html