Software Architecture

Question 1

What is Single Responsibilty Principle?

Answer 1

A Module should be responsible to one and only one, actor. or one reason to change.
It says to separate the code that different actors depend upon

Question 2

Dependency Inversion is based on What?

Answer 2

Polymorphism(Runtime)

Question 3

What is OO?

Answer 3

OO is the ability, through the
use of polymorphism, to gain absolute control over every source code
dependency in the system. It allows the architect to create a plugin architecture,
in which modules that contain high-level policies are independent of modules
that contain low-level details.

Question 4

How to protect Component A from changes in Component B ?

Answer 4

Make Component B depend on Component A

Question 5

What is OCP at Architecture level?

Answer 5

Higher Level Components must be protected from the changes in Lower Level components

Question 6

What are Components ?

Answer 6

Components are units of deployment

Question 7

What are Components in Java , .NET ?

Answer 7

JAR files are Components in JAVA . DLLs are components in .NET

Question 8

When to use singleton DI?

Answer 8

Singletons are suitable for objects that need to be shared across the entire application

Question 9

When to use Transient DI?

Answer 9

Objects that are short-lived and created on demand

Question 10

When to use Scoped DI?

Answer 10

Objects that should maintain state for a session

Question 11

What is Web Server?

Answer 11

Web servers deliver responses to simple requests . They primarily use http also support ftp and smtp. They deliver content like HTML pages , images , videos and files. Do not typically use multithreading

Question 12

What is application server?

Answer 12

Delivere more complex content from databases , services and enterprise systems . They support many protocols and deliver dynamic content , like real-time updates, personalized information and customer support. Uses multithreading to process requests concurrently

Question 13

What is web service server?

Answer 13

This server handles web service requests like API services etc . This service is accessed via HTTP typically an API to be used by programs

Question 14

What is circuit breaker?

Answer 14

Circuit breaker is a state machine that starts in closed state and allows the flow if requests across it. When a problem is detected the circuit breaker moves to open state blocking all the requests for specific period. After this period , it moves to half open state where the first request is treated as test request . If request suceeds circuit closes and normal operation resumes , but if it fails the circuit moces back to open and remains there for a specific period before moving to half open again

Question 15

What is circuit breaker in .net core?

Answer 15

It is a design pattern to improve the resilience and fault tolerance of applications that interact with external services or resources

Question 16

What are transpilers?

Answer 16

Source to source compilers . They are a subset of compilers which take in a source code and convert it to another source code file in some other language or a different version of the same language generally understandable by a human

Question 17

Why do we use logging frameworks to to create logs?

Answer 17

To avoid performance overhead , log to different sources like console , files , sampling , to log serializable data that can be further used for analysis like JSON

Question 18

What does cerificate mean?

Answer 18

If a website has a valid certificate, it means a certificate authority had taken steps to verify that the address actually belongs to that organization

Question 19

What does browser do with certificates?

Answer 19

When you type url or click on link to a secure website, browser will check the certificate for
1. Website address matches the address on certificate
2.certificate is signed by a certificate authority that the browser recognizes as a ‘trusted’ authority

Question 20

What are public and private certificates?

Answer 20

Public certificates are needed for digital projects that can be viewed publicly - by anyone surfing internet or other user community. Whereas, private trust provides a secure srrvice for internal IT environments that gives more time to evolve the systems to more stringent requirements needed for public trust

Question 21

What is Microsoft Entra ID?

Answer 21

Creating apps maintaining own username and password incurs a high administrative burden when adding or removing users. Instead , your apps can delegate that responsibility to a centralized identity provider. Microsoft Entra ID is a centralized identity provider in the cloud.

Question 22

What are advantages of Microsoft Entra ID?

Answer 22

1. Conditional access policies - user needs to be in specific location
2. MFA
   3.Enabling user to sign in once and then automatically signed in to all the webapps that share the same centralized directory- Single Sign-On(SSO)

Question 23

What is purge?

Answer 23

Systematically removing unnecessary files and applications to optimize performance

Question 24

What is the issue with standard HTTP request/response pattern?

Answer 24

If the application runs on mutiple computers or even open in multiple windows on the same computer, then the updates made through this process would not be visible in real time- until the page is refreshed

Question 25

What is long polling?

Answer 25

First attempt to create a lower- latency communication standard is known as long-polling. It consisted of jeeping the connection made after an initial HTTP request open, in order to allow the server to respond at a later time.

Question 26

What is the issue with long polling?

Answer 26

For larger applications, with more users and requests and a larger database long-polling could become a very resource intensive solution and was not well suited for applications that require low latency. It also still required a connection setup and frequent request-response exchanges

Question 27

What is web socket protocol?

Answer 27

Initially, an HTTP handshake is made between participating client and server and then it is moved to web socket protocal where both client and server continue to communicate in a full duplex, persistent connection, connection is maintained for as long as application is running

Question 28

What are progressive webapps?

Answer 28

A progressive web app(PWA) is an app that’s built using web platform technologies, but that provides a user experience like that of a platform-specific app

Question 29

Can progressive website run on multiple platforms and devices?

Answer 29

Like a website, a PWA can run on mutiple platforms and devices from a single codebase. Like a platform-specific app, it can be installed on the device, can operate while offline and in the background, and can integrate with the device and other installed apps

Question 30

What does threadsafe mean?

Answer 30

A code or datastructure is threadsafe when the outcome of the code and underlying resources do not create undesirable results because of multiple threads interacting with code concurrently