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HDFS, mail # dev - Hadoop-2 generics compilation error


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Re: Hadoop-2 generics compilation error
Alejandro Abdelnur 2012-06-29, 22:26
Andy,

It looks like OpenJDK javac does not handle type unboxing with a
generic method where the parameter that resolves the generic infers
the type to do the un-boxing on. While SunJDK does handle it.

Now, to the question which one is correct? I'm not sure but SunJDK
does a valid inference.

thx

On Fri, Jun 29, 2012 at 2:43 PM, Andy Isaacson <[EMAIL PROTECTED]> wrote:
> I've filed https://issues.apache.org/jira/browse/HDFS-3580 and attached the
> patch.
>
> I'd really appreciate it if someone could explain what the problem is, why
> the patch fixes it, and whether this is a bug in OpenJDK (that it does not
> accept a valid program) or a bug in Sun JDK (that it does accept an
> incorrect program).
>
> -andy
>
> On Fri, Jun 29, 2012 at 12:01 PM, Andy Isaacson <[EMAIL PROTECTED]> wrote:
>
>> I ran into this as well, and am prepping a patch. Lars, if you could file
>> the Jira explaining why s/boolean/Boolean/ is the right fix, I'll test and
>> submit the patch.
>>
>> -andy
>>
>>
>> On Fri, Jun 29, 2012 at 11:08 AM, Alejandro Abdelnur <[EMAIL PROTECTED]>wrote:
>>
>>> This change is from HDFS-3481, the wrong JIRA number is because I made
>>> a mistake in the commit message.
>>>
>>> I can put a patch to fix this, but don't have OpenJDK to test it. It
>>> would be better if somebody with OpenJDK takes care of it and I'll
>>> review it.
>>>
>>> Thx
>>>
>>> On Fri, Jun 29, 2012 at 11:01 AM, Arun C Murthy <[EMAIL PROTECTED]>
>>> wrote:
>>> > HDFS-3113 is committed? Or, are you running with the patch yourself?
>>> >
>>> > It's still PA and I see Daryn reviewing it yet...
>>> >
>>> > Arun
>>> >
>>> > On Jun 28, 2012, at 10:27 PM, lars hofhansl wrote:
>>> >
>>> >> Since HDFS-3113 was integrated into Hadoop-2 I get the compilation
>>> errors of the following type:
>>> >>
>>> >> [ERROR]
>>> /home/lars/dev/hadoop-2/hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/fs/http/server/HttpFSServer.java:[407,36]
>>> incompatible types; no instance(s) of type variable(s) V exist so that V
>>> conforms to boolean
>>> >>
>>> >>
>>> >> Indeed at line 407 I see:
>>> >>
>>> >>         boolean hasData = params.get(DataParam.NAME, DataParam.class);
>>> >>
>>> >>
>>> >> When I change that to
>>> >>         Boolean hasData = params.get(DataParam.NAME, DataParam.class);
>>> >>
>>> >>
>>> >> instead (along with long to Long, short to Short, etc, later in that
>>> file), everything compiles fine.
>>> >>
>>> >> $ javac -version
>>> >> javac 1.6.0_24
>>> >>
>>> >>
>>> >> $ java -version
>>> >> java version "1.6.0_24"
>>> >> OpenJDK Runtime Environment (IcedTea6 1.11.3)
>>> (fedora-67.1.11.3.fc16-x86_64)
>>> >> OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)
>>> >>
>>> >> Apparently OpenJDK gets mixed up on the type inference here. Can we
>>> change this in the way I suggest so that Hadoop-2 (and presumably trunk)
>>> can be
>>> >> compiled with OpenJDK?
>>> >> I'm happy to create a jira and (trivial) patch.
>>> >>
>>> >>
>>> >> Thanks.
>>> >>
>>> >> -- Lars
>>> >>
>>> >
>>> > --
>>> > Arun C. Murthy
>>> > Hortonworks Inc.
>>> > http://hortonworks.com/
>>> >
>>> >
>>>
>>>
>>>
>>> --
>>> Alejandro
>>>
>>
>>

--
Alejandro