[jira] [Commented] (SOLR-14236) 【solr】 A "org.apache.log4j.ConsoleAppender" object is not assignable to a "org.apache.log4j.Appender" variable.

["Shawn Heisey (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SOLR-14236?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17029274#comment-17029274 ] 

Shawn Heisey commented on SOLR-14236:
-------------------------------------

Solr 4.10.1 has been unsupported for a VERY long time.  Current versions are 8.x, so 8.x is fully supported, and there is some limited support for the latest 7.x version.

Additionally, we do not support running Solr in Tomcat.  I haven't heard of being able to *build* Solr in Tomcat before.  Solr is currently built by ant.

---

The jars that you mentioned are used by Solr for logging.  Solr itself uses slf4j for logging, which is a framework that allows the final logging destination to be decided when the complete application is assembled.  Some of Solr's dependencies directly use JDK logging, Apache Commons Logging, and log4j.

The finished Solr package that is part of the download uses log4j as the final logging destination ... so jars are required to capture logs from JDK logging and Apache Commons Logging and inject them into slf4j.

If you want to run any version of Solr in Tomcat, you should download Solr and place the completed binary webapp into Tomcat.  You will need to deal with the logging jars yourself.  The installation of Jetty that is in the download is set up to use log4j 1.x as the final destination as of version 4.3, and log4j 2.x as of version 7.4.

[https://cwiki.apache.org/confluence/display/SOLR/WhyNoWar]

> 【solr】 A "org.apache.log4j.ConsoleAppender" object is not assignable to a "org.apache.log4j.Appender" variable.
> ---------------------------------------------------------------------------------------------------------------
>
>                 Key: SOLR-14236
>                 URL: https://issues.apache.org/jira/browse/SOLR-14236
>             Project: Solr
>          Issue Type: Bug
>      Security Level: Public(Default Security Level. Issues are Public) 
>          Components: Server, SolrJ
>    Affects Versions: 4.10.1
>            Reporter: Jenny Qiu
>            Priority: Minor
>              Labels: solr, tomcat
>         Attachments: 微信截图_20200203224606.png
>
>
>  
> I have built the solr project through tomcat, but when I run the startup.bat it tells me this: 
> {code:java}
> log4j:ERROR A "org.apache.log4j.ConsoleAppender" object is not assignable to a "org.apache.log4j.Appender" variable.
> log4j:ERROR The class "org.apache.log4j.Appender" was loaded by
> log4j:ERROR [org.powermock.core.classloader.MockClassLoader@16a40b2] whereas object of type
> {code}
> I searched for many solutions online, but none works.
>  
> Then I thought maybe things went wrong with the files related to log4j, then I deleted the *log4j-1.2.17.jar* in _D:\FSP_20160630\apache-tomcat-8_0_9-solr4_10_1\webapps\solr\WEB-INF\lib_ because I can find exact {color:#FF0000}same{color} ones in _D:\FSP_20160630\apache-tomcat-8_0_9-solr4_10_1\lib_
> _!微信截图_20200203224606.png!_
> But I need to mention that i have also deleted the other 3 files, or I will get another error:
>  
> {code:java}
> ContextListenerjava.lang.LinkageError: loader constraint violation: when resolving method
> "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader 'org.apache.catalina.loader.WebappClassLoader@4d1cc3c3 (urls: ['], parents: [)'java.net.URLClassLoader@4fccd51b']) of the current class, org/slf4j/LoggerFactory, and the class loader ...{code}
>  
> In conclusion, I have deleted all these 4 files, then the startup.bat can run properly.
> I don't know whether things will go south in the future...Are these files useful in the solr\WEB-INF\lib? Can they be deleted like this?
> Hope I can get some instructions, thx for your time!
>  



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