All time favorite!

Following are some of my all time favorite interview questions:

• What are SOLID Design Principals?
• What is SRP?
• What is the difference between HastTable and a Dictionary?
• How does a hast table or dictionary work under the hood?
• Why is string class immutable in .net?
• What is hybrid dictionary?
• What are extension methods?
• When to use an interface and an abstract class?
• When should ConcurrentDictionary class be used?
• What is yield key word in c#?
• Why would you ever need to make a custom class immutable?
• How does Garbage Collector work in .net?
• How to make singleton design pattern thread safe?
• Difference between Lock, Semaphore and Mutex?
• Difference between Auto and Manual Reset Event ?
• Difference between a hash table and a table variable in SQL?