Part I (closed)

Question 1

Odpowiednik repozytorium i UoW w EF?

Answer 1

DbSet i DbContext

Question 2

What is kernel responsible for?

Answer 2

CPU, RAM, I/O

Question 3

What is virtual addressing?

Answer 3

Layer of abstraction between process and memory. If not enough available memory then writing to disk happens.

Question 4

Describe interrupts on example of disk?

Answer 4

Processor asks disk for data but doesn’t wait for the result but comes back to executing some other work. When disk is ready it interrupts the processor.

Question 5

What’s the purpose of expression trees?

Answer 5

To translate code into data that can be then translated e.g. into string (LINQ to SQL) and executed somewhere

Question 6

Difference between arithmetic and logical bit shift?

Answer 6

Arithmetic right shift includes the sign but while logical uses zeros.

Question 7

Template method vs strategy?

Answer 7

Template uses inheritance, strategy uses interfaces, more runtime. Template method can substitute only part of algorytm that is the derived class.

Question 8

What is IOCP?

Answer 8

I/O completion port - API in Windows for asynchronous I/O operations

Question 9

What thread pools are there in .NET how they are different?

Answer 9

Worker Process Thread Pool and IOCP Thread Pool. IOCP uses OS-managed queue while worker process thread pool uses managed .NET queue.

Question 10

How is thread pool related to application domain?

Answer 10

Each app domain has its own thread pool.

Question 11

Why and when setting min threads in thread pool can be advantageous?

Answer 11

When app has to deal with many requests at once. Thread pool is updated every 500ms and then additional threads are eventually created.

Question 12

What is preemptive multithreading?

Answer 12

A situation in which a thread can be suspended after reading a variable from memory but before manipulating it and storing in the memory.

Question 13

Database denormalization

Answer 13

Keeping redundant data in tables if very much data in Db and joins could cost too much.

Question 14

Describe 3 normal forms of a database

Answer 14

First that each column has only one piece of information (eg separate columns for different address parts). Second that each category of information should be stored separately and keys should be introduced. Third that each informational column that can be computed from others should be dropped.

Question 15

What is a ViewBag?

Answer 15

One way of providing data to a view in ASP.NET MVC.

It is not strongly typed. Preferred way of providing data is through a view model.

Question 16

How is editing/delete done in controllers (GET/POST)

Answer 16

Basically there are two methods with the same name, one is get and second is post.

Question 17

What is salting a password?

Answer 17

An operation in which user’s password is combined with a dynamically generated salt (value) and a hash function generates a hash from it. Then hash and salt is stored in a database. Protects against dictionary attack, rainbow table attack. The same password has different hash for different instances.

Question 18

How to suggest eager loading to EF?

Answer 18

By using include method.

Question 19

Difference between eager loading and lazy loading?

Answer 19

Eager loading tries to use one query with join while lazy loading uses multiple queries.

Question 20

What’s the most important factor in Kanban?

Answer 20

WiP - Work in Progress, defines how many items can be placed in each Kanban’s board column, if there are too much work whole team should help

Question 21

Relation of Scrum to agile?

Answer 21

Agile is an idea, a specification while Scrum is a specific framework.

Question 22

When to use GET method in ASP.NET MVC form?

Answer 22

When e.g. searching by filters and we want to see the filter in URL so that some other people can copy them and use.

Question 23

What convention is used by default with GET method and database?

Answer 23

That all methods not changing database can be queried using GET.

Question 24

What is HATEOAS and HAL?

Answer 24

HATEOAS (Hypermedia as the engine of application state) is a concept in which contract between client and server is not express through IDL or interfaces but is dynamically managed by hypermedia (e.g. bank account with dynamic actions depending on its state). HAL is just implementation of HATEOAS.

Question 25

How is rendering done in ASP.NET?

Answer 25

Aspx files are turned into initialization class (with its partial classes), which in turn creates a tree which in turn is traversed using visitor pattern.

Question 26

Three ways of session variable persistence in ASP.NET?

Answer 26

In-process (recycled when ASP.NET process recycled)
State server - using special ASP.NET session service
SQL Server mode - using SQL database

Question 27

What is a session in ASP.NET?

Answer 27

Subsequent queries from the same browser sent during a specified period.

Question 28

What are some other methods of state management than session state?

Answer 28

Application state, cookies, cache, query string, view state.

Question 29

What is a view state in ASP.NET?

Answer 29

A way of state management for the same page betwen round trips e.g. restoring data from form. View state is a serialized state of all controls on the page sent to browser as base64 as hidden field. It can be also persisted on the server.

Question 30

What is the order in DataContractSerializer, is it important?

Answer 30

Base class properties, alphabetically (for properties without order set), according to order attribute. It’s important in serialization and deserialization especially when interoperability (Joomla PHP to ASP MVC)

Question 31

What is templating, how it works in ASP.NET?

Answer 31

Templating is reusing a part of a page (e.g. master page) when generating pages. It can be done on the server side, client side, proxy side. In ASP.NET there’s a concept of master pages.

Question 32

What is ASP.NET performance?

Answer 32

It’s better than scripting engines (like ASP for example). Code is compiled into MSIL during first request to a page. It can cause a short delay for the first time a page is used.

Question 33

What is AJAX?

Answer 33

Asynchronous JavaScript and XML, although today most often JSON, set of technologies (HTML, CSS, JavaScript, DOM). Generally JavaScript call and asynchronous response from server which changes the web page.

Question 34

What’s the newer construction to XmlHttpRequest? How is AJAX executed in JQuery?

Answer 34

fetch, in jquery its $.ajax or even $.get done failed

Question 35

How are TDD and BDD similar and different?

Answer 35

Both are based on tests. But BDD uses more descriptive, natural ways of describing requirements. Code written in BDD is in plain English which can be easily understood by all stakeholders in comparison to TDD. Both can be used in agile TDD test written by developers while BDD can be written by product manager and even understood by user

Question 36

How to delete object with references in EF?

Answer 36

Null parent properties of objects being deleted.

Question 37

What is seeding a database in EF?

Answer 37

Code First Migrations can be enabled in a project. Migrations folder is created with classes with methods Up, Down, Seed. Seed inserts data.

Question 38

How validation is done in ASP MVC?

Answer 38

Locally by jquery script and on the server. If importing jqueryval is commented for example then server validates. Result the same.

Question 39

What’s the order rule in ASP.NET routing?

Answer 39

Most specific routes first.