How to prevent an object from getting garbage collected?

Question

How to prevent an object from getting garbage collected?

Are there any approaches by finalize or phantom reference or any other approaches?

I was asked this

Answer 1

This sounds like one of those interview-only-time-you'll-see-it questions. finalize() is run when your object is getting garbage collected, so it'd be pretty perverse to put something in there to prevent collection. Normally you just hold a reference and that's all you need.

I'm not even sure what would happen if you'd create a new reference for something in the finalizer - since the garbage collector's already decided to collect it would you then end up with a null ref? Seems like a poor idea, in any case. e.g.

public class Foo {
   static Foo reference;
  ...
  finalize (){ 
     reference = this; 
  }
}

I doubt this would work, or it might work but be dependant on the GC implenetation, or be "unspecified behavior". Looks evil, though.