JDK 9 pre-review of JDK-6850612: Deprecate Class.newInstance since it violates the checked exception language contract

[David Holmes]

I agree with Stuart.

David

On 19/04/2016 9:05 AM, Stuart Marks wrote:
>
>
> On 4/17/16 10:31 AM, joe darcy wrote:
>> With talk of deprecation in the air [1], I thought it would be a fine
>> time to
>
> "In the Spring a young man's fancy lightly turns to thoughts of
> deprecation."
>      -- apologies to Tennyson
>
>> examine one of the bugs on my list
>>
>>      JDK-6850612: Deprecate Class.newInstance since it violates the
>> checked
>> exception language contract
>>
>> As the title of the bug implies, The Class.newInstance method
>> knowingly violates
>> the checking exception contract. This has long been documented in its
>> specification: [...]
>>
>> Comments on the bug have suggested that besides deprecating the
>> method, a new
>> method on Class could be introduced,
>> newInstanceWithProperExceptionBehavior,
>> that had the same signature but wrapped exceptions thrown by the
>> constructor
>> call in the same way Constructor.newInstance does.
>
> Deprecating Class.newInstance() seems reasonable to me, for the reasons
> you've stated.
>
> It's not clear to me that a replacement method adds much value. I
> believe it's possible to replace a call
>
>      clazz.newInstance()  // 1
>
> with the call
>
>      clazz.getConstructor().newInstance()  // 2
>
> which is only a bit longer. Both snippets are declared to throw
> InstantiationException and IllegalAccessException. But snippet 2 also is
> declared to throw InvocationTargetException and NoSuchMethodException.
>
> This would seem to be an inconvenience, but *all* of these exceptions
> are subtypes of ReflectiveOperationException. It seems pretty likely to
> me that most code handles these different exception types the same way.
> So it's fairly low cost to replace snippet 1 with snippet 2, and to
> adjust the exception handling to deal with ReflectiveOperationException.
> Thus I don't see much value in adding a new method such as
> Class.newInstanceWithProperExceptionBehavior().
>
> s'marks