Mine

  <target name="compile" depends="init"
        description="compile the source " >
    <!-- Compile the java code from ${src} into ${build} -->
    <mkdir dir="${build}/classes" />
    <javac srcdir="${src}" destdir="${build}/classes"/>
    <classpath>
        <pathelement path="${classpath}"/>
        <fileset dir="lib">
            <include name="**/*.jar"/>
        </fileset>
    </classpath>