Friday, June 7, 2013

Some Interview questions by Scott Hansleman

As I follow him very closely and don't want to loos these questions from his blog. I just copied here.  I also has to prepare some of them.   
  • What is something substantive that you've done to improve as a developer in your career? 
  • Would you call yourself a craftsman (craftsperson) and what does that word mean to you? 
  • Implement a <basic data structure> using <some language> on <paper|whiteboard|notepad>. 
  • What is SOLID? 
  • Why is the Single Responsibility Principle important? 
  • What is Inversion of Control? How does that relate to dependency injection? 
  • How does a 3 tier application differ from a 2 tier one? 
  • Why are interfaces important? 
  • What is the Repository pattern? The Factory Pattern? Why are patterns important? 
  • What are some examples of anti-patterns? 
  • Who are the Gang of Four? Why should you care? 
  • How do the MVP, MVC, and MVVM patterns relate? When are they appropriate? 
  • Explain the concept of Separation of Concerns and it's pros and cons. 
  • Name three primary attributes of object-oriented design. Describe what they mean and why they're important. 
  • Describe a pattern that is NOT the Factory Pattern? How is it used and when? 
  • You have just been put in charge of a legacy code project with maintainability problems. What kind of things would you look to improve to get the project on a stable footing? 
  • Show me a portfolio of all the applications you worked on, and tell me how you contributed to design them. 
  • What are some alternate ways to store data other than a relational database? Why would you do that, and what are the trade-offs? 
  • Explain the concept of convention over configuration, and talk about an example of convention over configuration you have seen in the wild. 
  • Explain the differences between stateless and stateful systems, and impacts of state on parallelism. 
  • Discuss the differences between Mocks and Stubs/Fakes and where you might use them (answers aren't that important here, just the discussion that would ensue). 
  • Discuss the concept of YAGNI and explain something you did recently that adhered to this practice. 
  • Explain what is meant by a sandbox, why you would use one, and identify examples of sandboxes in the wild. 
  • Concurrency 
  • What's the difference between Locking and Lockless (Optimistic and Pessimistic) concurrency models? 
  • What kinds of problems can you hit with locking model? And a lockless model? 
  • What trade offs do you have for resource contention? 
  • How might a task-based model differ from a threaded model? 
  • What's the difference between asynchrony and concurrency? 
  • Are you still writing code? Do you love it? 
  • You've just been assigned to a project in a new technology how would you get started? 
  • How does the addition of Service Orientation change systems? When is it appropriate to use? 
  • What do you do to stay abreast of the latest technologies and tools? 
  • What is the difference between "set" logic, and "procedural" logic. When would you use each one and why? 
  • What Source Control systems have you worked with? 
  • What is Continuous Integration? Have you used it and why is it important? 
  • Describe a software development life cycle that you've managed. 
  • How do you react to people criticizing your code/documents? 
  • Whose blogs or podcasts do you follow? Do you blog or podcast? 
  • Tell me about some of your hobby projects that you've written in your off time. 
  • What is the last programming book you read? 
  • Describe, in as much detail as you think is relevant, as deeply as you can, what happens when I type "cnn.com" into a browser and press "Go". 
  • Describe the structure and contents of a design document, or a set of design documents, for a multi-tiered web application. 
  • What's so great about <cool web technology of the day>? 
  • How can you stop your DBA from making off with a list of your users’ passwords? 
  • What do you do when you get stuck with a problem you can't solve? 
  • If your database was under a lot of strain, what are the first few things you might consider to speed it up? 
  • What is SQL injection? 
  • What's the difference between unit test and integration test? 
  • Tell me about 3 times you failed. 
  • What is Refactoring ? Have you used it and it is important? Name three common refactorings. 
  • You have two computers, and you want to get data from one to the other. How could you do it? 
  • Left to your own devices, what would you create? 
  • Given Time, Cost, Client satisfaction and Best Practices, how will you prioritize them for a project you are working on? Explain why. 
  • What's the difference between a web server, web farm and web garden? How would your web application need to change for each? 
  • What value do daily builds, automated testing, and peer reviews add to a project? What disadvantages are there? 
  • What elements of OO design are most prone to abuse? How would you mitigate that? 
  • When do you know your code is ready for production? 
  • What's YAGNI? Is this list of questions an example? 
  • Describe to me some bad code you've read or inherited lately. 

What Great .NET Developers Ought To Know

Everyone who writes code

  • Describe the difference between a Thread and a Process? 
  • What is a Windows Service and how does its lifecycle differ from a "standard" EXE? 
  • What is the maximum amount of memory any single process on Windows can address? Is this different than the maximum virtual memory for the system? How would this affect a system design? 
  • What is the difference between an EXE and a DLL? 
  • What is strong-typing versus weak-typing? Which is preferred? Why? 
  • Corillian's product is a "Component Container." Name at least 3 component containers that ship now with the Windows Server Family. 
  • What is a PID? How is it useful when troubleshooting a system? 
  • How many processes can listen on a single TCP/IP port? 
  • What is the GAC? What problem does it solve?

Mid-Level .NET Developer

  • Describe the difference between Interface-oriented, Object-oriented and Aspect-oriented programming. 
  • Describe what an Interface is and how it’s different from a Class. 
  • What is Reflection? 
  • What is the difference between XML Web Services using ASMX and .NET Remoting using SOAP? 
  • Are the type system represented by XmlSchema and the CLS isomorphic? 
  • Conceptually, what is the difference between early-binding and late-binding? 
  • Is using Assembly.Load a static reference or dynamic reference? 
  • When would using Assembly.LoadFrom or Assembly.LoadFile be appropriate? 
  • What is an Asssembly Qualified Name? Is it a filename? How is it different? 
  • Is this valid? Assembly.Load("foo.dll"); 
  • How is a strongly-named assembly different from one that isn’t strongly-named? 
  • Can DateTimes be null? 
  • What is the JIT? What is NGEN? What are limitations and benefits of each? 
  • How does the generational garbage collector in the .NET CLR manage object lifetime? What is non-deterministic finalization? 
  • What is the difference between Finalize() and Dispose()? 
  • How is the using() pattern useful? What is IDisposable? How does it support deterministic finalization? 
  • What does this useful command line do? tasklist /m "mscor*" 
  • What is the difference between in-proc and out-of-proc? 
  • What technology enables out-of-proc communication in .NET? 
  • When you’re running a component within ASP.NET, what process is it running within on Windows XP? Windows 2000? Windows 2003?

Senior Developers/Architects

  • What’s wrong with a line like this? DateTime.Parse(myString); 
  • What are PDBs? Where must they be located for debugging to work? 
  • What is cyclomatic complexity and why is it important? 
  • Write a standard lock() plus “double check” to create a critical section around a variable access. 
  • What is FullTrust? Do GAC’ed assemblies have FullTrust? 
  • What benefit does your code receive if you decorate it with attributes demanding specific Security permissions? 
  • What does this do? gacutil /l | find /i "Corillian" 
  • What does this do? sn -t foo.dll 
  • What ports must be open for DCOM over a firewall? What is the purpose of Port 135? 
  • Contrast OOP and SOA. What are tenets of each? 
  • How does the XmlSerializer work? What ACL permissions does a process using it require? 
  • Why is catch(Exception) almost always a bad idea? 
  • What is the difference between Debug.Write and Trace.Write? When should each be used? 
  • What is the difference between a Debug and Release build? Is there a significant speed difference? Why or why not? 
  • Does JITting occur per-assembly or per-method? How does this affect the working set? 
  • Contrast the use of an abstract base class against an interface? 
  • What is the difference between a.Equals(b) and a == b? 
  • In the context of a comparison, what is object identity versus object equivalence? 
  • How would one do a deep copy in .NET? 
  • Explain current thinking around IClonable. 
  • What is boxing? 
  • Is string a value type or a reference type? 
  • What is the significance of the "PropertySpecified" pattern used by the XmlSerializer? What problem does it attempt to solve? 
  • Why are out parameters a bad idea in .NET? Are they? 
  • Can attributes be placed on specific parameters to a method? Why is this useful? 

C# Component Developers

  • Juxtapose the use of override with new. What is shadowing? 
  • Explain the use of virtual, sealed, override, and abstract. 
  • Explain the importance and use of each component of this string: Foo.Bar, Version=2.0.205.0, Culture=neutral, PublicKeyToken=593777ae2d274679d 
  • Explain the differences between public, protected, private and internal. 
  • What benefit do you get from using a Primary Interop Assembly (PIA)? 
  • By what mechanism does NUnit know what methods to test? 
  • What is the difference between: catch(Exception e){throw e;} and catch(Exception e){throw;} 
  • What is the difference between typeof(foo) and myFoo.GetType()? 
  • Explain what’s happening in the first constructor: public class c{ public c(string a) : this() {;}; public c() {;} } How is this construct useful? 
  • What is this? Can this be used within a static method?

ASP.NET (UI) Developers

  • Describe how a browser-based Form POST becomes a Server-Side event like Button1_OnClick. 
  • What is a PostBack? 
  • What is ViewState? How is it encoded? Is it encrypted? Who uses ViewState? 
  • What is the <machinekey> element and what two ASP.NET technologies is it used for? 
  • What three Session State providers are available in ASP.NET 1.1? What are the pros and cons of each? 
  • What is Web Gardening? How would using it affect a design? 
  • Given one ASP.NET application, how many application objects does it have on a single proc box? A dual? A dual with Web Gardening enabled? How would this affect a design? 
  • Are threads reused in ASP.NET between reqeusts? Does every HttpRequest get its own thread? Should you use Thread Local storage with ASP.NET? 
  • Is the [ThreadStatic] attribute useful in ASP.NET? Are there side effects? Good or bad? 
  • Give an example of how using an HttpHandler could simplify an existing design that serves Check Images from an .aspx page. 
  • What kinds of events can an HttpModule subscribe to? What influence can they have on an implementation? What can be done without recompiling the ASP.NET Application? 
  • Describe ways to present an arbitrary endpoint (URL) and route requests to that endpoint to ASP.NET. 
  • Explain how cookies work. Give an example of Cookie abuse. 
  • Explain the importance of HttpRequest.ValidateInput()? 
  • What kind of data is passed via HTTP Headers? 
  • Juxtapose the HTTP verbs GET and POST. What is HEAD? 
  • Name and describe at least a half dozen HTTP Status Codes and what they express to the requesting client. 
  • How does if-not-modified-since work? How can it be programmatically implemented with ASP.NET?
  • Explain <@OutputCache%> and the usage of VaryByParam, VaryByHeader. 
  • How does VaryByCustom work? 
  • How would one implement ASP.NET HTML output caching, caching outgoing versions of pages generated via all values of q= except where q=5 (as in http://localhost/page.aspx?q=5)?

Developers using XML

  • What is the purpose of XML Namespaces? 
  • When is the DOM appropriate for use? When is it not? Are there size limitations? 
  • What is the WS-I Basic Profile and why is it important? 
  • Write a small XML document that uses a default namespace and a qualified (prefixed) namespace. Include elements from both namespace. 
  • What is the one fundamental difference between Elements and Attributes? 
  • What is the difference between Well-Formed XML and Valid XML? 
  • How would you validate XML using .NET? 
  • Why is this almost always a bad idea? When is it a good idea? myXmlDocument.SelectNodes("//mynode"); 
  • Describe the difference between pull-style parsers (XmlReader) and eventing-readers (Sax) 
  • What is the difference between XPathDocument and XmlDocument? Describe situations where one should be used over the other. 
  • What is the difference between an XML "Fragment" and an XML "Document." 
  • What does it meant to say “the canonical” form of XML? 
  • Why is the XML InfoSet specification different from the Xml DOM? What does the InfoSet attempt to solve? 
  • Contrast DTDs versus XSDs. What are their similarities and differences? Which is preferred and why? 
  • Does System.Xml support DTDs? How? 
  • Can any XML Schema be represented as an object graph? Vice versa? 

~ Cheers
Happy hunting. 

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