CODEWITHSUNDEEP
c#.net
user9623401
user9623401

Reputation:

All types have Finalize method inherited from Object?

We know that when a type override Finalize method, it must survive the garbage collection, it gets promoted to another generation, forcing the object to live much longer than it should. This is not ideal in terms of memory consumption and is why you should avoid finalization when possible.

But isn't that all type implicitly derived from Object, and Object does have a default Finalize method, so CLR should consider all types have Finalize method and therefore all objects on the heap will get prompted to new generation, and live longer than they should?

Upvotes: 0

Views: 205

Answers (1)

V0ldek
V0ldek

Reputation: 10573

As @canton7 said in a comment, the runtime is smart enough to know that if there are no finalizers in the instance's inheritance chain other than Object.Finalize then it does not have to mark the instance for finalization. The relevant part of the documentation is:

The Object class provides no implementation for the Finalize method, and the garbage collector does not mark types derived from Object for finalization unless they override the Finalize method.

Interestingly enough, neither the C# specification nor the ECMA CLI specification enforce this behaviour. It is permitted for a conforming implementation of the runtime to always schedule all objects for finalization. However, as you recognised in the question, this would cause an enormous overhead in garbage collection so it would be impractical.

Note: the relevant sections are §8.9 and §15.2 for the C# spec and I.8.9.6.7 of the ECMA CLI spec.

Upvotes: 3

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