Caused By: java.lang.NoClassDefFoundError: org/apache/log4j/Logger

I've got an interesting problem in which the org.apache.log4j.Logger class is not found during runtime. I'm trying to get authorized and that is where it's failing:

OAuthAuthorizer oauthAuthorizer = new OAuthAuthorizer(OAUTH_CONSUMER_KEY, OAUTH_CONSUMER_SECRET, SAML_PROVIDER_ID, userId);

I'm using JDeveloper 11.1.1.6. Here is what I know:

1. I've looked in my UI.war/WEB-INF/lib directory and I see the log4j-1.2.17.jar there.

2. The class complaining about it is org.opensaml.xml.XMLConfigurator

    Caused by: java.lang.NoClassDefFoundError: org/apache/log4j/Logger
    	at org.opensaml.xml.XMLConfigurator.<clinit>(XMLConfigurator.java:60)
    	at org.opensaml.DefaultBootstrap.initializeXMLTooling(DefaultBootstrap.java:195)
    	at org.opensaml.DefaultBootstrap.bootstrap(DefaultBootstrap.java:91)
    	at com.intuit.ipp.aggcat.util.SAML2AssertionGenerator.getSAMLBuilder(SAML2AssertionGenerator.java:156)
    	at com.intuit.ipp.aggcat.util.SAML2AssertionGenerator.createSubject(SAML2AssertionGenerator.java:187)
    	at com.intuit.ipp.aggcat.util.SAML2AssertionGenerator.buildAssertion(SAML2AssertionGenerator.java:114)
    	at com.intuit.ipp.aggcat.util.SAML2AssertionGenerator.generateSignedAssertion(SAML2AssertionGenerator.java:83)
    	at com.intuit.ipp.aggcat.util.SamlUtil.createSignedSAMLPayload(SamlUtil.java:156)
    	at com.intuit.ipp.aggcat.util.OAuthUtil.getOAuthTokens(OAuthUtil.java:60)
    	at com.intuit.ipp.aggcat.core.OAuthAuthorizer.<init>(OAuthAuthorizer.java:85)
    	at com.incomemax.view.intuit.WebUtil.getAggCatService(WebUtil.java:91)
   

    Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Logger
    	at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    	at java.security.AccessController.doPrivileged(Native Method)
    	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:305)
    	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:246)
    	... 64 more
   

3. I decomplied XMLConfigurator and oddly it doesn't import org.apache.log4j.Logger It uses org.slf4j.Logger which is also in my jars directory (slf4j-api-1.7.5.jar). Also interesting is that line 60 (see stack trace) is a blank line in my decompile.

4. Of course if I add Logger.xxxxx during design time, it finds it just fine.

5. I'm using the code/jars directly from the sample java code, but imported into my existing application.

I've been scouring the web for answers and I believe I've checked all the areas I can think of. I also referenced this very good page: http://myarch.com/classnotfound/

Given authorization is step 1 in using the Intuit Developer API, I'm kinda stuck.

Adding output from @jhadesdev suggestion:

All versions of log4j Logger:

• zip:C:/Users/Chris/AppData/Roaming/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/tmp/_WL_user/j2ee-app/lt5l71/war/WEB-INF/lib/log4j-1.2.17.jar!/org/apache/log4j/Logger.class

All versions of log4j visible from the classloader of the OAuthAuthorizer class:

• zip:C:/Users/Chris/AppData/Roaming/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/tmp/_WL_user/j2ee-app/lt5l71/war/WEB-INF/lib/log4j-1.2.17.jar!/org/apache/log4j/Logger.class

All versions of XMLConfigurator:

• jar:file:/C:/Oracle/Middleware11116/modules/com.bea.core.bea.opensaml2_1.0.0.0_6-1-0-0.jar!/org/opensaml/xml/XMLConfigurator.class

• zip:C:/Users/Chris/AppData/Roaming/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/tmp/_WL_user/j2ee-app/lt5l71/war/WEB-INF/lib/ipp-java-aggcat-v1-devkit-1.0.2.jar!/org/opensaml/xml/XMLConfigurator.class

• zip:C:/Users/Chris/AppData/Roaming/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/tmp/_WL_user/j2ee-app/lt5l71/war/WEB-INF/lib/xmltooling-1.3.1.jar!/org/opensaml/xml/XMLConfigurator.class

All versions of XMLConfigurator visible from the class loader of the OAuthAuthorizer class:

• jar:file:/C:/Oracle/Middleware11116/modules/com.bea.core.bea.opensaml2_1.0.0.0_6-1-0-0.jar!/org/opensaml/xml/XMLConfigurator.class

• zip:C:/Users/Chris/AppData/Roaming/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/tmp/_WL_user/j2ee-app/lt5l71/war/WEB-INF/lib/ipp-java-aggcat-v1-devkit-1.0.2.jar!/org/opensaml/xml/XMLConfigurator.class

• zip:C:/Users/Chris/AppData/Roaming/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/tmp/_WL_user/j2ee-app/lt5l71/war/WEB-INF/lib/xmltooling-1.3.1.jar!/org/opensaml/xml/XMLConfigurator.class

I'm still working on interpreting the results.

During runtime your application is unable to find the jar.

Taken from this answer by Jared:

> It is important to keep two different exceptions straight in our head > in this case: > > 1. java.lang.ClassNotFoundException This an Exception, it indicates that the > class was not found on the classpath. This indicates that we were > trying to load the class definition, and the class did not exist on > the classpath. >
>
> 2. java.lang.NoClassDefFoundError This is Error, it indicates that the JVM > looked in its internal class definition data structure for the > definition of a class and did not find it. This is different than > saying that it could not be loaded from the classpath. Usually this > indicates that we previously attempted to load a class from the > classpath, but it failed for some reason - now we're trying again, > but we're not even going to try to load it, because we failed > loading it earlier. The earlier failure could be a > ClassNotFoundException or an ExceptionInInitializerError (indicating > a failure in the static initialization block) or any number of other > problems. The point is, a NoClassDefFoundError is not necessarily a > classpath problem.

for similarities and differences

You can use the following maven dependency in your pom file. Otherwise, you can download the following two jars from net and add it to your build path.

<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-api</artifactId>
	<version>1.6.4</version>
</dependency>

<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-log4j12</artifactId>
	<version>1.6.4</version>
</dependency>

This is copied from my working project. First make sure it is working in your project. Then you can change the versions to use any other(versions) compatible jars.

For AggCat, you can refer the POM file of the sample java application.

https://github.com/IntuitDeveloperRelations/IPP_Sample_Code/blob/master/CustomerAccountData/Java/AggCatSampleApplication/pom.xml

Thanks

Check in Deployment Assembly,

I have the same error, when i generate the war file with the "maven clean install" way and deploy manualy, it works fine, but when i use the runtime enviroment (eclipse) the problems come.

The solution for me (for eclipse IDE) go to: "proyect properties" --> "Deployment Assembly" --> "Add" --> "the jar you need", in my case java "build path entries". Maybe can help a litle!

Based on the stacktrace, an intuit class com.intuit.ipp.aggcat.util.SAML2AssertionGenerator needs a saml jar on the classpath.

A saml class org.opensaml.xml.XMLConfigurator needs on it's turn log4j, which is inside the WAR but cannot find it.

One explanation for this is that the class XMLConfigurator that needs log4j was found not inside the WAR but on a downstream classloader. could a saml jar be missing from the WAR?

The class XMLConfigurator that needs log4j cannot find it at the level of the classloader that loaded it, and the log4j version on the WAR is not visible on that particular classloader.

In order to troubleshoot this, a way is to add this before the oauth call:

System.out.println("all versions of log4j Logger: " + getClass().getClassLoader().getResources("org/apache/log4j/Logger.class") );

System.out.println("all versions of XMLConfigurator: " + getClass().getClassLoader().getResources("org/opensaml/xml/XMLConfigurator.class") );

System.out.println("all versions of XMLConfigurator visible from the classloader of the OAuthAuthorizer class: " + OAuthAuthorizer.class.getClassLoader().getResources("org/opensaml/xml/XMLConfigurator.class") );

System.out.println("all versions of log4j visible from the classloader of the OAuthAuthorizer class: " + OAuthAuthorizer.class.getClassloader().getResources("org/apache/log4j/Logger.class") );

Also if you are using Java 7, have a look at jHades, it's a tool I made to help troubleshooting these type of problems.

In order to see what is going on, could you post the results of the classpath queries above, for which container is this happening, tomcat, jetty? It would be better to put the full stacktrace with all the caused by's in pastebin, just in case.

With the suggestions @jhadesdev and the explanations from others, I've found the issue here.

After adding the code to see what was visible to the various class loaders I found this:

All versions of log4j Logger: 
  zip:<snip>war/WEB-INF/lib/log4j-1.2.17.jar!/org/apache/log4j/Logger.class

All versions of log4j visible from the classloader of the OAuthAuthorizer class: 
  zip:<snip>war/WEB-INF/lib/log4j-1.2.17.jar!/org/apache/log4j/Logger.class
  
All versions of XMLConfigurator: 
  jar:<snip>com.bea.core.bea.opensaml2_1.0.0.0_6-1-0-0.jar!/org/opensaml/xml/XMLConfigurator.class
  zip:<snip>war/WEB-INF/lib/ipp-java-aggcat-v1-devkit-1.0.2.jar!/org/opensaml/xml/XMLConfigurator.class
  zip:<snip>war/WEB-INF/lib/xmltooling-1.3.1.jar!/org/opensaml/xml/XMLConfigurator.class

All versions of XMLConfigurator visible from the classloader of the OAuthAuthorizer class: 
  jar:<snip>com.bea.core.bea.opensaml2_1.0.0.0_6-1-0-0.jar!/org/opensaml/xml/XMLConfigurator.class
  zip:<snip>war/WEB-INF/lib/ipp-java-aggcat-v1-devkit-1.0.2.jar!/org/opensaml/xml/XMLConfigurator.class
  zip:<snip>war/WEB-INF/lib/xmltooling-1.3.1.jar!/org/opensaml/xml/XMLConfigurator.class

I noticed that another version of XMLConfigurator was possibly getting picked up. I decompiled that class and found this at line 60 (where the error was in the original stack trace) private static final Logger log = Logger.getLogger(XMLConfigurator.class); and that class was importing from org.apache.log4j.Logger!

So it was this class that was being loaded and used. My fix was to rename the jar file that contained this file as I can't find where I explicitly or indirectly load it. Which may pose a problem when I actually deploy.

Thanks for all help and the much needed lesson on class loading.

Had the same problem, it was indeed caused by weblogic stupidly using its own opensaml implementation. To solve it, you have to tell it to load classes from WEB-INF/lib for this package in weblogic.xml:

    <prefer-application-packages>
        <package-name>org.opensaml.*</package-name>
    </prefer-application-packages>

maybe <prefer-web-inf-classes>true</prefer-web-inf-classes> would work too.

java.lang.ClassNotFoundException is indicate that class is not found in class path. it could be the version of log4j is not compatible. check for different log4j version.

I had the same issue, for me this fixed the issue:
right click on the project ->maven -> update project

Add compile 'org.apache.logging.log4j:log4j-1.2-api:2.17.1' and then it will automatically work

In my case, the error was due to some dependencies using log4j v 1.x that I removed from the classpath. So I introduced the log4j-1.2-api to bridge v 1.x to 2.x as recommended in the Apache Migration guide:

After introducing this dependency in my build.gradle, the error disappeared :

implementation 'org.apache.logging.log4j:log4j-1.2-api:2.17.+!!'