What great .NET developers ought to know

Excerpted from http://www.hanselman.com/blog/WhatGreatNETDevelopersOughtToKnowMoreNETInterviewQuestions.aspx

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?

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?