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From Ceki Gülcü <>
Subject Re: [GUMP@brutus]: jakarta-commons/commons-logging failed
Date Wed, 19 May 2004 09:00:50 GMT
At 11:23 PM 5/17/2004, robert burrell donkin wrote:

>>Ceki Gülcü wrote:
>>>Fortunately, the required changes are easy and are backward compatible.
>>>Commons-logging code needs to be changed as follows.
>>The change was in the Category class, formerly the log methods accepted a 
>>priority but this has change to a level now.
>>But it looks like the change isnt really backward compatible, i have 
>>tried this now and got the following exception (patched commons-logging 
>>and log4j-1.2.8):
>(as i read the language specification 2.0 anyway) this change should be 
>compile compatible but not binary compatible. (i think that the cause is 
>that in java the method overload algorithm is executed at compile time - 
>see sections 13.2 and 15.2.)
>nice if ceki (or someone else from log4j) could confirm that this change 
>is incompatible.

Experiments I conducted also show that while it is fairly easy to
modify commons-logging to make it compile-time compatible with both
log4j 1.2 and 1.3alpha.

However, at runtime, commons-logging source compiled with
log4j-1.2.x.jar will run with log4j-1.2.x.jar but not
log4j-1.3alpha.jar. Similarly, the *same* commons-logging source code
will compile fine with log4j-1.3alpha.jar but it will only with
log4j-1.3alpha.jar, log4j-1.2.x.jar.

In summary, the changes proposed by Mario Ivankovits and myself
achieve compile-time compatibility but not run-time compatibility.

>- robert

Ceki Gülcü

      For log4j documentation consider "The complete log4j manual"
      ISBN: 2970036908  

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