build.xml

<?xml version="1.0"?>
<project name="Ant-Build" default="run" basedir=".">
	<!-- Sets variables which can later be used. -->
	<!-- The value of a property is accessed via ${} -->
	<property name="src.dir" location="src" />
	<property name="build.dir" location="bin" />
	<property name="dist.dir" location="jar" />
	
	<!-- Deletes the existing build  directory-->
	<target name="clean">
		<delete dir="${build.dir}" />
		<delete dir="${dist.dir}" />
	</target>

	<!-- Creates the  build, docs and dist directory-->
	<target name="makedir">
		<mkdir dir="${build.dir}" />
		<mkdir dir="${dist.dir}" />
	</target>

	<!-- Compiles the java code   -->
	<target name="compile" depends="clean, makedir">
		<javac srcdir="${src.dir}" destdir="${build.dir}">
		</javac>
	</target>

	<!--Creates the deployable jar file  -->
	<target name="jar" depends="compile">
		<jar destfile="${dist.dir}\myBuild.jar" basedir="${build.dir}">
			<manifest>
				<attribute name="Main-Class" value="Main" />
			</manifest>
		</jar>
	</target>

	<!-- This is picked up by eclipse. click on the button to run! --> 
	<target name="run"  depends="compile, jar">
		<description>Execute the Jar and sets input file as STDIN</description>
		<java jar="${dist.dir}\myBuild.jar" fork="true" input="input.txt"/>
	</target>
	
</project>