Re: JavaMemoryModel: Interaction between the memory model and exceptions

From: Jeremy Manson (jmanson@cs.umd.edu)
Date: Sat Apr 10 2004 - 10:32:13 EDT


[Charset iso-8859-1 unsupported, filtering to ASCII...]
> Bottom line is that I think the JMM needs to discuss these issues.

Why is any of this any different from what 11.3.1 implies, and what must
already be implemented by VMs? If we aren't really changing anything, and
it isn't part of Chapter 17, why do we need to discuss it?

> Async exceptions caused by internal VM errors seem more problematic as these
> literally appear to occur "inside" the execution of a bytecode. And given
> the VM doesn't really expect them to happen, catering for their memory
> semantics seems rather ambitious. My feeling is that in practice the
> internal error is of far more concern than the imprecise nature of the
> exception.

Here's an interesting post on the matter from Cliff Click when he was
working at Sun:

> Sun's certainly gone to some length to make sure StackOverflowError
> appears to be thrown at some particular point. InternalErrors are
> never thrown because we don't have recoverable errors; i.e. the VM
> crashes instead. :-)

I suppose it is fine to have precise semantics for something that never
happens.

                                        Jeremy
-------------------------------
JavaMemoryModel mailing list - http://www.cs.umd.edu/~pugh/java/memoryModel



This archive was generated by hypermail 2b29 : Thu Oct 13 2005 - 07:01:03 EDT