simple, naive, build.xml that works but is probably not very good in several ways

build.xml

<project name="keywords">
    <property name="main-class" value="com.keywords.Person"/>
    <property name="lib.dir" value="lib"/>
    <property name="build.dir" value="bin"/>
    <property name="app.dir" value="src/main/java"/>
    <property name="test.dir" value="src/test/java"/>
    <property name="jar.dir" value="dist"/>

    <path id="classpath">
        <fileset dir="${lib.dir}" includes="**/*.jar"/>
    </path>

    <target name="compile">
        <mkdir dir="${build.dir}"/>
        <javac srcdir="${app.dir}" destdir="${build.dir}" classpathref="classpath"/>
    </target>

    <target name="jar" depends="compile">
        <mkdir dir="${jar.dir}"/>
        <jar destfile="${jar.dir}/${ant.project.name}.jar" basedir="${build.dir}">
            <manifest>
                <attribute name="Main-Class" value="${main-class}"/>
            </manifest>
        </jar>
    </target>

    <target name="compile-tests" depends="compile">
        <mkdir dir="${build.dir}"/>
        <javac srcdir="${test.dir}" destdir="${build.dir}" classpathref="classpath"/>
    </target>

    <target name="test" depends="compile-tests,jar">
        <junit printsummary="yes">
            <classpath>
                <path refid="classpath"/>
                <pathelement location="${jar.dir}/${ant.project.name}.jar"/>
            </classpath>

            <batchtest fork="yes">
                <fileset dir="${test.dir}"/>
            </batchtest>
        </junit>
    </target>
</project>