[LOGGING-45] Default LogFactory Implementation fails for Log4J : ClassCastException

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0
• Fix Version/s: 1.0.3

Environment

Operating System: other
Platform: Other

• Bugzilla Id: 9845
• Assignee: Unassigned
• Reporter: Jerome Jacobsen
• Created: 13/Jun/02 23:26
• Updated: 29/Dec/09 17:08
• Resolved: 18/Nov/06 12:48

Description

I've got Log4J 1.1.3 JAR in my classpath. Upon startup of my application
(actually a JUnit test case), I immediately get:

java.lang.ExceptionInInitializerError:
org.apache.commons.logging.LogConfigurationException:
java.lang.ClassCastException

So I downloaded the Commons Logging 1.0 source and debugged. The problem is in
org.apache.commons.logging.impl.LogFactoryImpl.guessConfig().

Class proxyClass=findClassLoader().
loadClass( "org.apache.commons.logging.Log4jFactory" );

The above loadClass call should be changed to:

Class proxyClass=findClassLoader().
loadClass( "org.apache.commons.logging.impl.Log4jFactory" );

However, after I make the above change I still get a ClassCastException, now
from org.apache.commons.logging.LogFactory.newFactory(). This exception
baffles me. It happens at:

return (LogFactory) clazz.newInstance();

So I modify newFactory() to do the newInstance() and the return in two steps
instead of one.

Object result = clazz.newInstance();
return (LogFactory)result;

The exception occurs during the cast of result. If I print result's class name
I get org.apache.commons.logging.impl.LogFactoryImpl. But checking if result
is an instanceof org.apache.commons.logging.impl.LogFactoryImpl returns false.

Object result = clazz.newInstance();
System.out.println("Got Factory: " + result.getClass().getName());

if (result instanceof LogFactory) {
System.out.println("result is a LogFactory");
}

if (result instanceof org.apache.commons.logging.impl.LogFactoryImpl) {
System.out.println("result is a LogFactoryImpl");
}

return (LogFactory) result;

The code above just prints:
Got Factory: org.apache.commons.logging.impl.LogFactoryImpl

And then throws the ClassCastException. I'm confused.