When does finalize method get called

Execution of an object's finalizer may be delayed for an arbitrarily long time after the object becomes unreachable. Consequently, invoking time-critical functionality such as closing file handles in an object's finalize method is problematic.

When is the finalize method called in Java? Just as a side note: finalize is marked as deprecated in Java 9 — Reg. It's deprecated starting Java9. In general it's best not to rely on finalize to do any cleaning up etc. According to the Javadoc which it would be worth reading , it is: Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. Unknown Unknown. Joachim Sauer Joachim Sauer. Object the method is called by the garbage collector when it determines no more references to the object exist the Object finalize method performs no actions but it may be overridden by any class normally it should be overridden to clean-up non-Java resources ie closing a file if overridding finalize it is good programming practice to use a try-catch-finally statement and to always call super.

XpiritO XpiritO. Check out Effective Java, 2nd edition page Item 7: Avoid finalizers Finalizers are unpredictable, often dangerous, and generally unnecessary. Hao Deng Hao Deng. If an object never becomes unreachable, finalize will never be called on it. It is hard to say, but there are a few possibilities: The object is not garbage collected because it is still reachable. The object is not garbage collected because the GC doesn't run before your test finishes. The object is found by the GC and placed in the finalization queue by the GC, but finalization isn't completed before your test finishes.

Stephen C Stephen C. Difficult to observe so we force JVM to call it by System. Pls slow down. Using VisualVM to observe as well as using weak references to track the actual interaction I found that following things are true in a Java 8 environment Oracle JDK, Ubuntu 15 : Finalize is not called immediately the Finalizer GC part individually owns the reference elusively The default Garbage Collector pools unreachable objects Finalize is called in bulk pointing to an implementation detail that there is a certain phase the garbage collector frees the resources.

Calling System. So if you have a lot of objects getting finalized the finalization phase will be triggered more often and earlier when compared with only a few There were circumstances a System. This might be generation related. Final Thought Finalize method is unreliable but can be used for one thing only.

Martin Kersten Martin Kersten. Generally an object becomes eligible for garbage collection in Java on following cases: All references of that object explicitly set to null e. Parent object set to null, if an object holds reference of another object and when you set container object's reference null, child or contained object automatically becomes eligible for garbage collection.

If an object has only live references via WeakHashMap it will be eligible for garbage collection. Tushar Trivedi Tushar Trivedi. Amarildo Amarildo. Java allows objects to implement a method called finalize that might get called. If the garbage collector doesn't run, the method doesn't get called. In practice, you are highly unlikely to use it in real projects. JavaDev JavaDev. Example: If your program end before garbage collector occur, then finalize will not execute.

AyukNayr AyukNayr. Utkarsh Utkarsh. October 9, at AM Kumaran said RajKumar, even clone method is declared as protected. July 2, at AM Anonymous said What's difference between finalize method and System. October 3, at AM Shantinath Chaudhary said October 6, at PM javin paul said October 8, at PM Andy said October 12, at AM Lorenzo Gomez said Great Article, thanks!

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