Why is the finalize() method in java.lang.Object “protected”?

Question

Out of curiosity,

Why is the finalize() method\'s access modifier is made as protected. Why cant it be public? Can someone exp

Answer 1

The part about finalize() being called only once applies only to the calls from the GC. You can imagine the object as having a hidden flag "finalize() was called by the GC", and the GC checking that flag to know what to do with the object. The flag is not impacted in any way by your own handmade calls to finalize().

On finalization, read this article from Hans Boehm (who is well-known for his work on garbage collection). This is an eye-opener about finalization; in particular, Boehm explains why finalization is necessarily asynchronous. A corollary is that while finalization is a powerful tool, it is very rarely the right tool for a given job.