Struts 1.2 and Commons Logging ClassLoader problem

Hi all,

I am fairly new to Struts, altho I have worked with several frameworks before. Trying to learn it from JakartaStrutsLive (can be downloaded from theserverside.com), I ran into a strange error connected to Commons logging.
The error message basically indicated that i have more than one piece of commons Log class loaded. I was just doing JUnit testing using StrutsTestCase (around page 70 of the tutorial), and got this message:

java.lang.ExceptionInInitializerError
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
at junit.framework.TestSuite.createTest(TestSuite.java:135)
at junit.framework.TestSuite.addTestMethod(TestSuite.java:114)
at junit.framework.TestSuite.<init>(TestSuite.java:75)
at junit.runner.BaseTestRunner.getTest(BaseTestRunner.java:103)
at junit.swingui.TestRunner.runSuite(TestRunner.java:591)
at junit.swingui.TestRunner.start(TestRunner.java:708)
at junit.swingui.TestRunner.main(TestRunner.java:52)
at junit.swingui.TestRunner.run(TestRunner.java:57)
at hu.juelsoft.junit.UserRegistrationActionTest.main(UserRegistrationActionTest.java:141)
Caused by: org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: 
Invalid class loader hierarchy.  
You have more than one version of 'org.apache.commons.logging.Log' visible, which is not allowed.         
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)

I checked the classpath for possible 2 instances of commons-logging.jar, but found none. When I removed the library, the compiler did not find the commons-related classes.

Checking on Google I found that some ppl already ran into this problem, but none had solutions so far.

Anyone can help, please ?
[ September 28, 2004: Message edited by: Gyula Klinszky ]

Oops, sorry for the formatting.