little bit of confusion about finalize method.

[dmjpro]

i know that the finalize method is called by JVM when an object is garbage collected.
right???
but the ultimate memory release done by native OS.

now my confusion is ... when it is called in reality?????

have a look at my code .....

import java.io.*;

class PariTest2
{
protected void finalize()
{
try{
FileWriter out = new FileWriter("d:/deb_web/lis/test_finalize.t xt");
out.write("Yaho o ... Finalize method gets called");
out.close();
System.out.prin tln("Yahoo ... Finalize method gets called");
}catch(Exceptio n e){
System.out.prin tln("DMJPRO: Error");
}
}
}

class FinalizeTest
{
public static void main(String a[])
{
System.out.prin tln("Main Thread starts");
new PariTest2();
}
}

when i can see the effect of finalize method calling????
plz help.

kind regards.
dmjpro.

[JosAH]

Finalize methods are a bit of a burden; the only thing that is guaranteed is that
they are invoked at most once and there's no guarantee when exactly they will
be invoked. But there's more misery going on; have a look at this:

public class Zombie {
   private static Zombie zz= null;
   public static void main(String[] args) {
      Zombie z= new Zombie();
      z= null; // object not reachable anymore
      System.gc();
      // assume that z's finalize method is called here
      zz.areYouAlive();
   }
   protected void finalize() { Zombie.zz= this; }
   public void areYouAlive() { System.out.println("boo!"); }
}

This filthy trick is named 'resurrection': when the garbage collector calls the
finalize() method on an obect because it can't be reached anymore, the object
itself makes itself reachable again. Finalize methods are a mess.

kind regards,

Jos

[dmjpro]

could u be more clearer????

thanks anyway.

kind regards.
dmjpro.

[JosAH]

could u be more clearer????

What was not clear about my reply? I know the 'resurrection' problem is
complicated by itself, but it was clearly explained in my reply. Read it again.

kind regards,

Jos

[dmjpro]

i don't understand that ...... when the garbage collector calls the
finalize() method on an obect because it can't be reached anymore, the object
itself makes itself reachable again. Finalize methods are a mess.

kind regards.
dmjpro.

[JosAH]

i don't understand that ...... when the garbage collector calls the
finalize() method on an obect because it can't be reached anymore, the object
itself makes itself reachable again. Finalize methods are a mess.

kind regards.
dmjpro.

Just what it reads: when the garbage collector is invoked it attempts to find
objects that are not referenced anywhere anymore: they are garbage. The
garbage collector invoked the finalize() method on those objects, but in my
example the object to be garbage collected makes itself reachable again
(see the code example: the object sets the zz static variable to itself) so it
cannot be garbage collected anymore. This is somethings that feels like a
contradiction and that's why I mentioned this example; something to think
about. Finalizers are a mess.

kind regards,

Jos