Why do finalizers have a “severe performance penalty”?

Question

Effective Java says :

There is a severe performance penalty for using finalizers.

Why is it slower to destroy an object using t

Answer 1

My thought is this: Java is a garbage collected language, which deallocates memory based on its own internal algorithms. Every so often, the GC scans the heap, determines which objects are no longer referenced, and de-allocates the memory. A finalizer interrupts this and forces the deallocation of memory outside of the GC cycle, potentially causing inefficiencies. I think best practices are to use finalizers only when ABSOLUTELY necessary such as freeing file handles or closing DB connections which should be done deterministically.