Ant Build To Create a Jar File

public class HelloWorld 
{
    public static void main(String args[]) 
    {
        System.out.println("Hello World");    
    }
}

<?xml version="1.0" ?>
<project name="FirstProject" basedir="." default="run">
    <property file="build.properties"/>

    <!-- description type -->
    <description>
    Project to create jar file
    </description>

    <target name="clean">
        <!-- Task to delete directory -->
        <delete dir="${build.dir}"/>
    </target>

    <target name="compile" depends="clean">
        <!-- Task to create directory -->
        <mkdir dir="${classes.dir}"/>
        <!-- Task to compile java classes -->
        <javac srcdir="${src.dir}" destdir="${classes.dir}"/>
    </target>

    <target name="jar" depends="compile">
        <!-- Task to create directory -->
        <mkdir dir="${jar.dir}"/>
        <!-- Task to create jar file with Main-Class assignment -->
        <jar destfile="${jar.dir}/${ant.project.name}.jar" basedir="${classes.dir}" excludes="**/Test.class">
            <manifest>
                <attribute name="Main-Class" value="${main-class}"/>
            </manifest>
        </jar>
    </target>

    <target name="run" depends="jar">
        <!-- Task to run the jar. Fork value true enables class execution in another JVM-->
        <java jar="${jar.dir}/${ant.project.name}.jar" fork="true"/>
    </target>

</project>

src.dir=src
build.dir=build
classes.dir=${build.dir}/classes
jar.dir=${build.dir}/jar
main-class=HelloWorld
archive.dir=archive
backup.dir=backup
util.dir=util

PS C:\Users\mail2\Downloads\Ant> ant
Buildfile: C:\Users\mail2\Downloads\Ant\build.xml

clean:
   [delete] Deleting directory C:\Users\mail2\Downloads\Ant\build

compile:
    [mkdir] Created dir: C:\Users\mail2\Downloads\Ant\build\classes
    [javac] C:\Users\mail2\Downloads\Ant\build.xml:19: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds
    [javac] Compiling 2 source files to C:\Users\mail2\Downloads\Ant\build\classes

jar:
    [mkdir] Created dir: C:\Users\mail2\Downloads\Ant\build\jar
      [jar] Building jar: C:\Users\mail2\Downloads\Ant\build\jar\FirstProject.jar

run:
     [java] Hello World

BUILD SUCCESSFUL