difference between destructor and garbage collector

Question

I want to know is there any difference between destructor and garbage collector, destructor is used to dispose of all unused objects at the end of the lifetime of the application, same is the use of the garbage collector, garbage collector can be manually called or done at the end of the application, same with the destructor, both are optional and use to dispose the unreferenced object, can anyone point me to whats the exact difference

Answer 1

The garbage collector and finalizer/destructor are intrinsically linked - however, most objects do not need (and do not have) a destructor. They are actually very rare in managed code, and are usually used to ensure unmanaged resources are released. If an object has a destructor/finalizer, the garbage collector invokes it around the same time as collection (maybe in the next pass). Garbage collection is non-deterministic - it happens when it happens - often relating to memory pressure.

Far more common, however, is IDisposable. This allows a more predictable pattern for releasing resources now (rather than when GC next happens). Often, classes that have a finalizer will also be IDisposable, with the Dispose() implementation disabling the destructor (it isn't needed if we've already cleaned up). Note that Dispose() is unrelated to garbage collection, but has language support via the "using" statement.

IDisposable is much more common than finalizers. You are responsible for ensuring anything IDisposable gets disposed. Additional note: disposing something does not cause the object to get collected; that is done only by the GC on whatever schedule the GC chooses. Disposal, rather, release associated resources. As an example, you wouldn't want a file being locked open until GC happens; the Dispose() here unlocks the file (by releasing the OS file handle).

Answer 2

The destructor is a special member function which is invoked when an object is destroyed. It is the last method run by a class.

The garbage collector is part of the framework, automatically manages memory, and non-deterministically collects unreferenced objects to avoid memory leaks.

Answer 3

The garbage collector is a part of the .NET environment that keeps track of objects and makes sure that objects are removed from memory when they are no longer needed.

A destructor is a part of a class design. It's the opposite of a constructor. When you declare it the GC will call it when it destroys an object.

Here is the MSDN documentation.