CODEWITHSUNDEEP
javaapacheweblogic-10.x
diazazar
diazazar

Reputation: 542

multiple classloader issue on weblogic

exception loader constraint violation: when resolving method "org.apache.hadoop.io.IOUtils.cleanup(Lorg/apache/commons/logging/Log;[Ljava/io/Closeable;)V" the class loader (instance of weblogic/utils/classloaders/ChangeAwareClassLoader) of the current class, org/apache/hadoop/hdfs/FileInputStreamCache, and the class loader (instance of weblogic/utils/classloaders/GenericClassLoader) for resolved class, org/apache/hadoop/io/IOUtils, have different Class objects for the type org/apache/commons/logging/Log used in the signature

I get this when using the application, not when deploying the ear. If i understand this wright, i have two classloaders that have two different logging objects? how can i refer them both to one?
EDIT 1
After further investigation, I think this error is due to the fact we are using a common jars library and there is another version of commons there, making them conflict. Is there any way to specify weblogic to use a specific library and not packaging? I would like to investigate this further

Upvotes: 2

Views: 3119

Answers (2)

Steve C
Steve C

Reputation: 19435

You need to check the WEB-INF/lib directory of your WAR files to ensure that they do not contain jars that also exist in the EAR/lib directory.

Web apps will always use the WEB-INF/lib classes before looking for them in the EAR file. However, classes loaded from the EAR will only see the other classes in the EAR. If you have the same (or similar) jar file in both places this will lead to class loading issues such as you describe.

Upvotes: 2

Biggy_java2
Biggy_java2

Reputation: 1951

You will have to update your weblogic-application.xml to use the use the prefer-application-package to tell the web logic to use the jar from the web-inf/lib instead of the jar from web logic. refer to the link Weblogic 10.3.5 Overriding Spring Version

<weblogic-application>
    <prefer-application-packages>
       <package-name>org.apache.*</package-name>
       <package-name>org.springframework.*</package-name>
    </prefer-application-packages>
</weblogic-application>

Upvotes: 2

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