I submitted my resume for the job on the Bloomberg internal career site. About a week later, I received an email asking to set up a phone interview. We agreed on a date and time for the following week.

The interview was conducted by a senior developer in the group I applied to. He began by asking what I knew about Bloomberg and my understanding of the role. This was followed by technical questions:

• What is a class?
• What is IDisposable?
• How do you define a value type? What is the difference between a class and a value type?
• Which class do all objects derive from? Which methods of this class might you want to override?
• What can you do with a delegate? How do you call a delegate asynchronously?
• What is the difference between a mutex and a monitor? What other synchronization objects do you know?
• How do you update a Windows UI from a background thread?

He concluded with a COM question, after asking if I knew or had used COM:

• What is IUnknown?

I answered all the questions, I believe correctly, except for the one about mutexes, monitors, and synchronization objects, and the one about updating the UI from a background thread.

The interview lasted about half an hour. Approximately two hours later, I received an email stating that they would not be offering me the job.

What is the difference between a mutex and a monitor?