Question

My java application uses log4j for logging. Using ant the project builds successfully, but I am unable to run it. The error I get is

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/Log
.........
Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.Log

My classpath contains the log4j jar.

[echo] ..../apache-log4j-1.2.15/log4j-1.2.15.jar: .....

My ant version is 1.7.1. What am I missing?

[Edit] My application is referencing another project which required the commons logging jar. So I tried creating an executable jar of the referenced project so that all the dependencies are carried over. The ant task to create the executable jar is as follows:

<target name="executablejar" depends="compile">
        <delete file="${dist}/app.jar" />

        <javac debug="true" srcdir="${src}" destdir="${classes}" classpath="${javac.classpath}"/>

        <copy todir="classes" flatten="true">
            <path>
                  <pathelement path="${javac.classpath}"/>
                </path>
        </copy>
        <jar jarfile="${dist}/app.jar" basedir="${classes}" />
</target>

However the error still persists. Am I creating the executable jar correctly?

Answer 1

You may have inadvertently imported a class from org.apache.commons.logging and now, as you might expect, the JVM is expecting to find the class definition on your classpath at runtime.

I’d recommend looking for usages of the commons-logging package in your code.