Help to solve problem with packaging log4j in a EAR file

Question

Hi All
i struggle hard to create a EAR composed of EJB JARs and WARs and the programs
in these JARs and WARs use log4j to log msg. Because i want all J2EE apps to have
their own version of log4j library, i package log4j.jar in the EAR file. Below
is my EAR package structure
EJB1.jar
EJB2.jar
SharedUtilities.jar
log4j.jar
log4j.properties
WEBAPP1.war
WEBAPP2.war
META-INF/manifest.mf
For both EJB1.jar and EJB2.jar's META-INF/manifest.mf, there is a below entries
Manifest-Version: 1.0
Class-Path: SharedUtilities.jar log4j.jar
However, my program always hit below runtime error.
[java] Caused by: javax.ejb.TransactionRolledbackLocalException: EJB Exception:
: java.lang.NoClassDefFoundError: org/apache/log4j/PropertyConfigurator
But the program in EJB1.jar and EJB2.jar seem to have no such problem in loading
classes in SharedUtilities.jar. The problem can be eliminated if i put log4j.jar
at system classpath. Can anybody provide me with info on how to package a log4j
library within a EAR package ?
In addition, where should i put the log4j.properties so that it will be at search
path of log4j and automatically loaded by log4j lib
regards
Danny

Answer 1

Hi Slava Imeshev
I am a bit confused about your reply. As said, the log4j.jar was packaged in my
ear file. If the log4j.jar was not packaged in ear file, how come the ejb classloader
can locate it.
Secondly, if log4j.jar is included in system classpath, the ejb also can load
log4j classes by system classloader. No "NoClassDeffound" exception is thrown.
regards
dso
"Slava Imeshev" <[email protected]> wrote:
"dso" <[email protected]> wrote in message
news:[email protected]...
Hi Slava Imeshev
thanks for your response. I am a bit confused about your answer.
i can't understand why u said the classloader COULD loadorg/apache/log4j/PropertyConfigurator.
According to the error msg, it said
" java.lang.NoClassDefFoundError: org/apache/log4j/PropertyConfigurator".
Seemingly,
this class in log4j.jar could not be located. But as i said in lastquestion,
i seemed to have properly
edit the "META-INF/manifest.mf" in EJB1.jar and EJB2.jar to includelog4j.jar
in "Class-path" attribute. And my EJB classes have no problem in loadingclasses
in SharedUtilities.jar. Would u please elaborate on it in more details?
Sure. NoClassDefFoundError means that a DEPENDING class
can not be loaded. If the classloader were not able to load the class
itself, it would give you ClassNotFoundException.
Just make sure that you don't have the same packages in
the ear and in the class path so that you don't have classes
loaded by system classloader trying to load classes loaded
by ejb classloaders.
regards
dso
"Slava Imeshev" <[email protected]> wrote:
First, this error means that classloader was able to load
org/apache/log4j/PropertyConfigurator, but cold not load
one of depending classes. I'd inspect the CLASSPATH
to see if there are any log4 classes there.
Second, you can package your log4.properties into
log4.jar itself.
Regards,
Slava Imeshev
"dso" <[email protected]> wrote in message
news:[email protected]...
Hi All
i struggle hard to create a EAR composed of EJB JARs and WARs and
the
programs
in these JARs and WARs use log4j to log msg. Because i want all
J2EE
apps
to have
their own version of log4j library, i package log4j.jar in the EARfile.
Below
is my EAR package structure
EJB1.jar
EJB2.jar
SharedUtilities.jar
log4j.jar
log4j.properties
WEBAPP1.war
WEBAPP2.war
META-INF/manifest.mf
For both EJB1.jar and EJB2.jar's META-INF/manifest.mf, there is
a below
entries
Manifest-Version: 1.0
Class-Path: SharedUtilities.jar log4j.jar
However, my program always hit below runtime error.
[java] Caused by: javax.ejb.TransactionRolledbackLocalException:EJB
Exception:
: java.lang.NoClassDefFoundError: org/apache/log4j/PropertyConfigurator
But the program in EJB1.jar and EJB2.jar seem to have no such problemin
loading
classes in SharedUtilities.jar. The problem can be eliminated if
i
put
log4j.jar
at system classpath. Can anybody provide me with info on how to
package
a
log4j
library within a EAR package ?
In addition, where should i put the log4j.properties so that it
will
be at
search
path of log4j and automatically loaded by log4j lib
regards
Danny