Updated ARM Spec

[Paul Benedict]

I still think Errors should not be swallowed. They indicate major
problems and should terminate the use case.

On Fri, Aug 20, 2010 at 3:45 PM, Joe Darcy <joe.darcy at oracle.com> wrote:
> Rémi Forax wrote:
>> Le 13/08/2010 05:28, Neal Gafter a écrit :
>>
>>> When a stack overflow exception suppresses another exception, I assume
>>> it's suppressed exception list will be set.  But since there is only
>>> one such exception allocated by the VM, this will overwrite any data
>>> previously stored there.  Will the VM be modified to comply with this
>>> specification by allocating a new stack-overflow exception each time?
>>> Same question for out-of-memory error.
>>>
>>>
>>
>> This problem already exists with jdk6.
>> This code change the stack trace of permanently allocated OutOfMerroryError.
>>
>>    public static void main(String[] args) {
>>      Error last = null;
>>
>>      for(int i=0; i<100; i++) {
>>        try {
>>          Object o = new int[Integer.MAX_VALUE];
>>        } catch (Error e) {
>>          StackTraceElement[] stackTrace = e.getStackTrace();
>>          if (stackTrace != null && stackTrace.length>0 &&
>> stackTrace[0].getLineNumber() == -3) {
>>            e.printStackTrace();
>>            return;
>>          }
>>
>>          if (last == e) {
>>            StackTraceElement element = new StackTraceElement("Foo",
>> "foo", null, -3);
>>            e.setStackTrace(new StackTraceElement[]{element});
>>          }
>>          last = e;
>>        }
>>      }
>>    }
>>
>>
>>
>> To avoid that the VM has to clear the stacktrace when using the default
>> error:
>> in universe.cpp, in Universe::gen_out_of_memory_error:
>>
>>    if (next < 0) {
>>        // all preallocated errors have been used.
>>        // return default
>> +    java_lang_Throwable::clear_stacktrace(default_err);
>>        return default_err;
>>      } else {
>>
>>
>> And we should do the same for the field suppressed exceptions.
>>
>> Rémi
>>
>>
>
> Thanks for the suggestion Rémi; I'm also checking with the HotSpot folks
> to see if any other kinds of exceptions need to be handled specially.
>
> -Joe
>
>