Why does GC need zap unused heap area?

[Y. Srinivas Ramakrishna]

It's just a debugging aid, an indicator that a specific portion of the 
heap has
not yet been allocated to a Java object. It happens when space is
first initialized into the heap (at initialization and space expansion)
and then when newly freed space is identified by GC at the end of
a collection (cycle). As you would have found, in product mode such
"zapping" is not done.

-- ramki

Colin(Du Li) wrote:
> Hi, guys,
>
> I have a question about GC.
> Why does GC need fill the unused heap area with "badHeapWordVal"
> ("0xbaadbabe")?
> And when does this happen?
>
> Thanks
>
> Du Li
>