How to set classpath order while building jar file using Ant?

Question

I am using zipgroupfileset to bundle all jars from lib folder to include in my executable application jar file.

<zipgroupfileset dir="${lib.dir}" />

Jars must be getting included in some default order. I want to alter this default order.

A note on why I want this: my Java desktop application uses many third party jars which are included in class path. When I run my code through Eclipse it works fine. But when I build the jar file using ANT it doesn't work as expected. I am sure it is related to jar sequence in classpath as if I change jar order in Eclipse it fails there as well.

Note: I am using Eclipse Kepler, Java 7, Ant 1.8.

Answer 1

Finally I got the solution. I build the Jar after altering my ANT file. Now my ANT build includes 3rd party APIs explicitly in classpath and that was the key to the solution.

<property name="lib.dir" value="lib" />

<manifestclasspath property="jar.classpath" jarfile="${lib.dir}/*.jar">
    <classpath refid="project.class.path"/>
</manifestclasspath>

<jar destfile="${jar.dir}/${jar.name}">
        <fileset dir="${class.root}" includes="**/*.*" />
        <manifest>
                <attribute name="Main-Class" value="${Main-Class}" />
                <attribute name="Class-Path" value="${jar.classpath}" />
        </manifest>
</jar>

Previously I had class-path entry in ANT as follows:

<attribute name="Class-Path" value="." />