Code review request for checked/unchecked exception clarifications

[David Holmes - Sun Microsystems]

Peter Jones said the following on 01/08/10 15:44:
> On Jan 8, 2010, at 12:16 AM, David Holmes - Sun Microsystems wrote:
>> Peter Jones said the following on 01/08/10 15:00:
>>> Hi.  Another nit: the wordings below seem to imply that "new Error()" and "new RuntimeException()" (i.e. not subclasses) make checked exceptions, but of course they are unchecked too.
>> What wording do you think implies this?
>>
>> These are quite clear:
>>
>> + * That is, {@code Error} and its subclasses are regarded as unchecked
>> + * exceptions for the purposes of compile-time checking of exceptions.
>>
>> + * <p>{@code RuntimeException} and its subclasses are <em>unchecked
>> + * exceptions</em>.
> 
> Yes, those seem fine-- I was referring to the excerpts that you had quoted earlier, from the Exception and Throwable docs:
> 
>>>>> + * <p>The class {@code Exception} and any subclasses that are not also
>>>>> + * subclasses of {@link RuntimeException} are <em>checked
>>>>> + * exceptions</em>.
>>>>>
>>>>> + * For the purposes of compile-time checking of exceptions, {@code
>>>>> + * Throwable} and any subclass of {@code Throwable} that is not also a
>>>>> + * subclass of either {@link RuntimeException} or {@link Error} are
>>>>> + * regarded as checked exceptions.
> 
> In JLS usage I don't think that subclass is a reflexive relation (like subtype is).  Compare the section 11.2 wording, "RuntimeException and its subclasses", etc.:
> 
> http://java.sun.com/docs/books/jls/third_edition/html/exceptions.html#44121

Ah I see. Yes in isolation those sentences do seem to exclude Error and 
RuntimeException themselves.

David