[vtkusers] java memory

[Sebastien Jourdain]

Hi Jonathan,

I directly reply on the context of your mail,


On Tue, Mar 29, 2011 at 2:33 AM, Jonathan Morra <jonmorra at gmail.com> wrote:
> Since I'm using vtkJavaGarbageCollector I'm already using
> vtkGlobalJavaHash.GC();.  The main questions that I currently still need
> answered are here
> 1.  should I have to call System.gc(); and System.runFinalization();
> frequently with VTK+Java?  It appears the memory is managed better when
> calling these lines every time vtkGlobalJavaHash.GC() is called, but I don't
> know if this is necessary.

System.gc(); is the only one that you should really care about. But
Java does not offer any guarantee if this method will do something or
not.  Moreover, the GC will stop all the thread to do its job. So it
is basically up to you.

> 2.  Is it ok to reuse Java variables?  Such as
> vtkImageData image = filter.GetOuput();
> // Do Stuff
> image = filter2.GetOuput();

yes

> 3.   Is it OK to move around java objects without an intermediate reference?
>  Such as
> image1.SetOutputSpacing(image2.GetSpacing());

what do you mean by Java object ? for me as the Set/Get do have a
capital letter, I would say they come from the VTK world and if they
return a vtkObject, you should use an intermediate variable otherwise
if it's an array of primary type, that is just fine.

> Sorry, forgot one more.  Should I be calling vtkGlobalJavaHash.GC() from the event dispatch thread?
> I saw that as an option in vtkJavaGarbageCollector, and I'm not sure why that's the case.

This totally depend on your VTK code, if you insure that all the call
you are doing on the VTK layer is done through the EDT, then you
should, otherwise you shouldn't. (This is a requirement if the data is
shown in a renderer.)

Seb