Java – Ant cannot find a class needed by an externally defined taskdef

antaxisclasspathjava

I am trying to use the axis-java2wsdl ant task to create a wsdl from one of my java classes, but I cannot get the classpath correct.

I am using Ubuntu's libaxis-java package which installs axis-ant.jar in $ANT_HOME/lib and axis.jar in /usr/share/java. The interesting parts of my build.xml look like this:

<property name="library.dir" value="lib"/>
<property name="system.library.dir" value="/usr/share/java"/>
<path id="libraries">
    <fileset dir="${library.dir}">
        <include name="*.jar"/>
    </fileset>
    <fileset dir="${system.library.dir}">
        <include name="*.jar"/>
    </fileset>
</path>

<target name="genwsdl" depends="compile">
    <taskdef resource="axis-tasks.properties" classpathref="libraries"/>
    <axis-java2wsdl>
            details omitted
    </axis-java2wsdl>
</target>

Running ant genwsdl results in:

/build.xml:50: taskdef A class needed by class
org.apache.axis.tools.ant.wsdl.Wsdl2javaAntTask
cannot be found: org/apache/axis/utils/DefaultAuthenticator

Ant is able to find the definition of the axis-java2wsdl task, because axis-ant.jar is in $ANT_HOME/lib, but it cannot find classes in axis.jar, even though that jar is on the path defined by "libraries"

I know it's a classpath issue because I was able to get past DefaultAuthenticator to other class's not found by symlinking axis.jar into $ANT_HOME/lib. How can I get the taskdef to recognize jar files in /usr/share/lib or my project's local lib directory without symlinking everything into $ANT_HOME/lib?

EDIT:

I was finally able to successfully generate the wsdl with this line:

ant -lib /usr/share/java/axis.jar -lib /usr/share/java/jaxrpc.jar -lib /usr/share/java/wsdl4j.jar -lib /usr/share/java/commons-logging.jar -lib /usr/share/java/commons-discovery.jar -lib build genwsdl

I would still very much appreciate if somebody could tell me what I'm doing wrong in not being able to define those libraries in build.xml

Best Answer

In general, this works. But you need to check very carefully which classes are where.

If your task class can be loaded in a classloader higher up in the classloader hierarchy (like CLASSPATH or ANT_HOME/lib) then your classpathref will simply get ignored.

Read the FAQ entry for more details.

Ant's class loader implementation uses Java's delegation model

The ClassLoader class uses a delegation model to search for classes and resources. Each instance of ClassLoader has an associated parent class loader. When called upon to find a class or resource, a ClassLoader instance will delegate the search for the class or resource to its parent class loader before attempting to find the class or resource itself. The virtual machine's built-in class loader, called the bootstrap class loader, does not itself have a parent but may serve as the parent of a ClassLoader instance.

Note: running ant -diagnostics can help too.

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