[External] : Re: Virtual thread memory leak because TrackingRootContainer keeps threads

[Ron Pressler]

> On 11 Jul 2024, at 12:38, Michal Domagala <outsider404 at gmail.com> wrote:
> 
> Regardless of the main issue, I understand that VT GC is problematic. JEP 444 is modified and GC paragraph is removed.
> VT created by Thread API is strongly referenced to avoid finalization problems

The reason for keeping a reference to virtual threads by default is not finalization but observability. The cost of holding a strong reference is near zero because we can rely on the same strong references in constructs such as Executors and StructuredTaskScope, while adding WeakReferences would come at a cost.

> 
> What does it mean? I do not understand this paragraph. Will G1 clean VT or not?

In most cases it will not because we keep a reference to the thread for observability unless you turn that off with a system property.

— Ron