System Design | Implementation Rule Book | CheatSheet

Instance Type/Series : Use cases T3/T4 [ Free trial]- Micro service, dev environment,,low CPU utilization and occasional periods for high CP...

 For versioning and organizing your database changes there are vwaios devops tools available in market.  The most known ones are  Liquibase ...

Opens-source Library : When to use What ? Chatbot - Apache Tensor Avoid DB Load: ehcache, Elastic Search Intelligence, running queries from ...

OAuth 2.0 uses Access Tokens and Refresh Tokens to secure access to applications and resources. Here is the flow: Obtaining OAuth 2.0 access...

Problem: ES Update fails due to Index becomes readOnly Root cause: Elasticsearch automatically sets "read_only_allow_delete": ...

 Writing code which talks is something the developer would love to have it. In this blog, we will talk about some of the mechanism which mak...

 In RabbitMQ, data safety is being handled by the below two mechanism:  I. Consumer Acknowledgements II.  Publisher confirms Consumer Acknow...

  docker --version   docker pull <image_name>   docker images  docker run -it -d <image_name>   docker ps  docker ps -a  docker ...

 Runnable JDK 1.0  new Thread( () -> System.out.println("Runnable") ).start() Callbale Java 5 Callable callable = Executors.cal...

  Read Lock: Read lock allows multiple thread to acquire lock in read method when all the synchronizing threads are using only the read lock...

 AmazonEBS :   High-availability block-level storage volumes for Amazon Elastic Compute Cloud (EC2) instances.  - It is paired with an EC2 i...

You can not allow xhr call to cross domain. Otherwise it would be very risky to allow third party script in your domain code. Here we will g...

 Designing a resilient architecture can comprise of following paradigm: I. Does your application has retrial mechanism? II. Is there any mec...

 JMX specification supports the following types of Bean: Standard MBeans Dynamic MBeans Open MBeans Model MBeans MXBeans  Managing Resource ...

While developing Spring based application there are instances where we would like to get a control of the spring beans. It comes very handy ...

 In today's world when the boilerplate code is readily available, write  minimum code and connect pluggable functionalities are the way ...

If you are looking for faster reads and writes in the background Elastic search framework suits it best. You don't need to add any cachi...

  Go Through HAR report and identify the backend services consuming maximum time. Now  identify the bottlenecks and  explore how the respons...

1.  Matching a set of words :  Hello Brick, Brik data ,Brck -->. Bri?c?k.   More: ^   Start                             $ End            ...

 In Software it is very essential to craft a solution which caters to the all possible requirements. Thus it would be generic enough to be a...

    Annotations are useful to tell: -Constraints or usage of an element: e.g. @Deprecated, @Override, or @NotNull - The "nature" o...

 There are various ways , the application can notify a set of recipients based on the error catrgories.  Spring email: configure logback xml...

 Spring retry is one of the implementation in Retryable Programming. Code snippet: Foo foo = template.execute(new RetryCallback<Foo>()...

 An application must be set with enough memory to be able to function as per the SLA. It should not be under or over utilised. Things to be ...

Redirect stderror to output $ cat foo.txt > output.txt 2>&1  // 2 stderror, &1 std output cat nopx.txt > outputx.txt 2>...

 #How to find process id of a running program on a given port sudo lsof   -i:8080 sudo lsof   -i:443

Secure shell:  Connect Remote server using SSH protocol -check existing key :ls -al ~/.ssh // It shows existing public and private key pair...

Real: wall clock time – time from start to finish of the call. User: the amount of CPU time spent in user-mode code (outside the kernel) w...

Steps to do rolling restart of ES cluster: sudo su root docker ps -a docker stop/start <I_ID> docker exec -it <IMG_Id> /bin/bash...

1.  Stream to Map Map<Integer, String> result3 = list.stream().collect( Collectors.toMap(x -> x.getId(), x -> x....

Creational Structural Behavioural Abstract Factory Assember Accumumator ...