Finalization

In object-oriented programming, finalization is the process of preparing an object for deallocation; strictly speaking, finalization is all parts of object destruction until memory deallocation itself. Finalization is formally complementary to initialization, which is the part of object creation that follows allocation, but differs significantly in practice – see contrast with initialization. Finalization fulfills a similar role as finally in exception handling; in general these are unrelated, but in some cases the behavior is identical, and the case of finally in a coroutine can be considered a form of finalization – see connection with finally. The term "final" is also used to indicate a class that cannot be inherited; this is unrelated.

Finalization varies significantly between languages and between implementations of a language, depending on memory management method, and can generally be partially controlled per-object or per-class by a user-specified finalizer or destructor, unlike deallocation. The terms "finalization" and "finalizer" are primarily used in languages with garbage collection, especially with non-deterministic object lifetimes, like Java; while "destruction" and "destructor" are used for languages with deterministic object lifetimes, like C++. This article addresses finalization in the broad sense, regardless of object lifetime or memory management method, but distinguishes how finalization differs depending on these.