Category: interview

• shared type system across all .net languages
• primitives data types library
• 5 kind of types:
  • classes
  • structures
  • enumerations
  • interfaces
  • delegates

Further read:

https://learn.microsoft.com/en-us/dotnet/standard/base-types/common-type-system

• provides a pool of threads
• can be used to execute tasks
• post work items
• process asynchronous I/O
• process timers

Further read:

https://learn.microsoft.com/en-us/dotnet/api/system.threading.threadpool?view=net-6.0

• simplify process of adding parallelism and concurrency to application
• scales concurrency automatically
• data parallelism
• task based async programming
• data flow

Further read:

https://learn.microsoft.com/en-us/dotnet/standard/parallel-programming/task-parallel-library-tpl

In short:

it will not work because it requires boxing and boxing will create new object for reference in lock every time code is executed so lock statement will not prevent anything.

Further read:

https://intellitect.com/blog/locking-a-block-of-code-with-an-integer/

• lock statement blocks execution of a code block for single thread that hold lock
• the same thread can acquire and release lock again
• any other thread is blocked from the statement
• lock on dedicated instance only
• using the same instance on multiple lock statements may lead to deadlock
• avoid using as lock
  • this, as it might be used by the callers as a lock
  • Type instances, as those might be obtained by the typeof operator or reflection
  • string instances, including string literals, as those might be interned
• Hold a lock for as short time as possible to reduce lock contention.

Below code block is translated by compiler

lock (x)
{
    // Your code...
}

to:

object __lockObj = x;
bool __lockWasTaken = false;
try
{
    System.Threading.Monitor.Enter(__lockObj, ref __lockWasTaken);
    // Your code...
}
finally
{
    if (__lockWasTaken) System.Threading.Monitor.Exit(__lockObj);
}

Further read:

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/statements/lock