build.xml

<project name="our-special-game" default="jarfile">

    <target name="init">
        <property name="project.name" value="PikachuJump"/>
        <property name="src.dir" value="src"/>
        <property name="main.class" value="game.Main"/>
        <property name="build.dir" value="build"/>
        <property name="classes.dir" value="${build.dir}/classes"/>
        <property name="resources.dir" value="resources"/>
        <property name="lib.dir" value="lib"/>
        <path id="classpath">
            <fileset dir="${lib.dir}"/>
        </path>
    </target>

    <target name="prepare" description="Creates the build and classes directories" depends="init">
        <mkdir dir="${classes.dir}"/>
    </target>

    <target name="compile" description="Compiles the source code" depends="prepare">
        <javac srcdir="${src.dir}" destdir="${classes.dir}" source="8" target="8">
            <classpath refid="classpath"/>
        </javac>
    </target>

    <target name="clean" description="Clean up" depends="init">
        <delete dir="${build.dir}"/>
    </target>

    <target name="jarfile" description="Archives the code" depends="compile">
        <jar destfile="build/${project.name}.jar" basedir="build/classes">
            <manifest>
                <attribute name="Main-Class" value="${main.class}" />
                <attribute name="Class-Path" value="${lib.dir}"/>
            </manifest>
            <zipgroupfileset dir="${lib.dir}"/>
            <fileset dir="${resources.dir}"/>
        </jar>
    </target>


</project>