Finalizers Are Not Destructors

C++ programmers tend to think that the finalize() method is equivalent to a destructor. This is not true, for two reasons:There is no guarantee that a finalizer will ever be called. Finalizers do not automatically propagate up the inheritance chain like destructors.It is clearly defined when a destructor will be executed- however it is undefined when a finalizer will be called. In particular, you should manually call super.finalize() from all your finalize methods. There is no guarantee about the order of invocation of finalizers. There are two System methods you should be aware of:

System.runFinalization() 
System.runFinalizersOnExit(boolean value)

System.runFinalization Runs the finalization methods of any objects pending finalization. System.runFinalizersOnExit is deprecated. It causes all finalizer methods to be invoked before exiting.

This method is inherently unsafe. It may result in finalizers being called on live objects while other threads are concurrently manipulating those objects, resulting in erratic behavior or deadlock.

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