apache ant是什么意思

<?xml version="1.0" ?> 
<project name="Hello World" default="execute">
<target name="init">
<mkdir dir="build/classes"/>
<mkdir dir="dist"/>
</target>
<target name="compile" depends="init">
<javac srcdir="src" destdir="build/classes"/>
</target>
<target name="compress" depends="compile">
        <jar destfile="dist/HelloWorld.jar" basedir="build/classes"  />
</target>
<target name="execute" depends="compile">
<java classname="HelloWorld" classpath="build/classes"/>
</target>
</project>