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

Daniel Fuchs daniel.fuchs at oracle.com
Wed Apr 27 14:20:58 UTC 2016

Hi Joe,

Changes in java.util.logging and java.management look good.

I glanced at the rest and spotted one issue here:


  615                 Object o = 
  616                 defaultParser = (Parser) o;

The call to newInstance() is missing at line 615

best regards,

-- daniel

On 21/04/16 18:25, joe darcy wrote:
> Hello,
> After a generally positive reception, please review the webrev to
> implement the deprecation of Class.newInstance and the suppression of
> the resulting warnings:
>     http://cr.openjdk.java.net/~darcy/6850612.0/
> There are also some changes in the langtools repo; I'll send a separate
> review request for those changes to compiler-dev.
> I'll also forward this review request to other areas with affected code.
> Thanks,
> -Joe
> On 4/17/2016 10:31 AM, joe darcy wrote:
>> Hello,
>> With talk of deprecation in the air [1], I thought it would be a fine
>> time to 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:
>>> Note that this method propagates any exception thrown by the nullary
>>> constructor, including a checked exception. Use of this method
>>> effectively bypasses the compile-time exception checking that would
>>> otherwise be performed by the compiler. The Constructor.newInstance
>>> method avoids this problem by wrapping any exception thrown by the
>>> constructor in a (checked) InvocationTargetException.
>> Roughly, the fix would be to turn the text of this note into the
>> @deprecated text and to add a @Deprecated(since="9") annotation to the
>> method. There are a few dozen uses of the method in the JDK that would
>> have to be @SuppressWarning-ed or otherwise updated.
>> Thoughts on the appropriateness of deprecating this method at this time?
>> 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.
>> Thanks,
>> -Joe
>> [1]
>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-April/040192.html

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