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Date: Wed, 30 Oct 2013 12:54:05 +0000
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 <CA+4kjVv2L1ntw128Q5JBbgZa6Aj=ivzgypFynyAxL2bmfV5A3w@mail.gmail.com>
Subject: Re: Question on hadoop dependencies.
From: Steve Loughran <stevel@hortonworks.com>
To: "common-dev@hadoop.apache.org" <common-dev@hadoop.apache.org>
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Why hello Peter,

Which version are you using?

The reason those dependencies are declared are because things like Jetty
use them -and the classpath for the server side Hadoop is "things needed to
run Hadoop".

Client-side I think there's too much in the maven dependency tree
(servlets, jetty, ...)


On 29 October 2013 19:22, Petar Tahchiev <paranoiabla@gmail.com> wrote:

> Hi guys,
>
> I'm using Spring-data-solr in my project. SDS declares Solr-core as a
> dependency. Solr declares hadoop-auth, hadoop-common, hadoop-hdfs
> dependencies. Each and every one of those dependencies declares log4j and
> slf4j-log4j12 as runtime dependencies, and also hadoop-common declares
> servlet-api version 2.5 as runtime dependency. So in the end I also get
> servlet-api 2.5, slf4 and log4j in my classpath.
> This normally shouldn't be a problem, but in my case I'm using Servlet 3.0,
> log4j2, and SL4j for log4j2. This completely messes up my classpath, so I
> have to manually exclude those dependencies, like this:
> -----------------------------------------------
>         <dependency>
>             <groupId>org.apache.solr</groupId>
>             <artifactId>solr-core</artifactId>
>             <version>${solr.version}</version>
>             <exclusions>
>                 <exclusion>
>                     <groupId>org.slf4j</groupId>
>                     <artifactId>slf4j-jdk14</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>org.apache.solr</groupId>
>                     <artifactId>solr-core</artifactId>
>                 </exclusion>
>             </exclusions>
>         </dependency>
>         <dependency>
>             <groupId>org.apache.solr</groupId>
>             <artifactId>solr-core</artifactId>
>             <version>${solr.version}</version>
>             <exclusions>
>                 <exclusion>
>                     <groupId>org.apache.hadoop</groupId>
>                     <artifactId>hadoop-auth</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>org.apache.hadoop</groupId>
>                     <artifactId>hadoop-common</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>org.apache.hadoop</groupId>
>                     <artifactId>hadoop-hdfs</artifactId>
>                 </exclusion>
>             </exclusions>
>         </dependency>
>         <dependency>
>             <groupId>org.apache.hadoop</groupId>
>             <artifactId>hadoop-auth</artifactId>
>             <version>${hadoop.version}</version>
>             <exclusions>
>                 <exclusion>
>                     <groupId>log4j</groupId>
>                     <artifactId>log4j</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>org.slf4j</groupId>
>                     <artifactId>slf4j-log4j12</artifactId>
>                 </exclusion>
>             </exclusions>
>         </dependency>
>         <dependency>
>             <groupId>org.apache.hadoop</groupId>
>             <artifactId>hadoop-common</artifactId>
>             <version>${hadoop.version}</version>
>             <exclusions>
>                 <exclusion>
>                     <groupId>log4j</groupId>
>                     <artifactId>log4j</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>org.slf4j</groupId>
>                     <artifactId>slf4j-log4j12</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>javax.servlet</groupId>
>                     <artifactId>servlet-api</artifactId>
>                 </exclusion>
>             </exclusions>
>         </dependency>
>         <dependency>
>             <groupId>org.apache.hadoop</groupId>
>             <artifactId>hadoop-hdfs</artifactId>
>             <version>${hadoop.version}</version>
>             <exclusions>
>                 <exclusion>
>                     <groupId>log4j</groupId>
>                     <artifactId>log4j</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>org.slf4j</groupId>
>                     <artifactId>slf4j-log4j12</artifactId>
>                 </exclusion>
>                 <exclusion>
>                     <groupId>javax.servlet</groupId>
>                     <artifactId>servlet-api</artifactId>
>                 </exclusion>
>             </exclusions>
>         </dependency>
> ---------------------------------------------------
> Just out of curiosity here - what is the reason to include log4j,
> slf4j-log4j12 and servlet-api as runtime dependencies? I think they should
> be with scope provided. It's good to program your API against slf4j, but
> then the connector should be specified by the user (Log4J2 in my case).
> Also are there any plans to migrate to Log4J2 - it seems pretty solid (9
> betas so far) and It is supposed to be released soon.
>
> Thanks for you time and keep up the good work.
>
> --
> Regards, Petar!
> Karlovo, Bulgaria.
> ---
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