Suggested fix for JDK-4724038 (Add unmap method to MappedByteBuffer)

David M. Lloyd david.lloyd at
Thu Sep 10 14:37:14 UTC 2015

Or, the Java methods which wrap this access can just catch NPE and throw 
the new exception type.

On 09/10/2015 09:35 AM, Vitaly Davidovich wrote:
> Well, you'd probably want something other than NPE here -- perhaps a new
> dedicated exception to signal this condition.  And this means the segfault
> handling now needs to know about this type of situation as well, rather
> than just NPEs.
> On Thu, Sep 10, 2015 at 10:32 AM, Andrew Haley <aph at> wrote:
>> On 09/10/2015 03:26 PM, Vitaly Davidovich wrote:
>>> Yes, so what happens when that guard page is accessed by a thread after
>> safepoint?
>> A segfault and a null pointer exception.
>> Andrew.


More information about the core-libs-dev mailing list