Finalization Reachable Table

Question

If I implement a destructor in a class, Foo, instances of Foo are tracked closely on the finalization queue. When an instance of Foo is garbage collected, I understand that the CLR sees the entry in the finalization queue and gives that object special treatment by moving the object off the heap and into the finalization reachable table. Then... nothing else happens for that garbage collection cycle?

Will finalize() always be called during the next garbage collection cycle?

Why isn't finalize called immediately after copying my object to the freachable table? (this seems like extra unnecessary complexity)

Answer 1

The finalizer queue is there to simplify things; it would be more complex without it. When the GC runs, no managed code must be executed - else all analysis that the GC had made might be void if user code runs in the middle.

So when the GC runs, finalization must be deferred, instead of getting executed right away. Running it in a separate thread minimizes the time that the VM requires exclusive access to all threads, and increases the potential for concurrent activities.