Create ant build on a demo project

Download ant zip from apache.org

Create a project - with java code in src directory

put the below xml as build.xml in same directory.

Run the ant from command line as 

>ant compile jar run

if you want to specify a special build file you can do so with 

> ant -buildfile build.xml compile jar run

<project>

   <target name="clean">

       <delete dir="build"/>

   </target>

   <target name="compile">

       <mkdir dir="build/classes"/>

       <javac srcdir="src" destdir="build/classes"/>

   </target>

   <target name="jar">

       <mkdir dir="build/jar"/>

       <jar destfile="build/jar/HelloWorld.jar" basedir="build/classes">

           <manifest>

               <attribute name="Main-Class" value="javatest.JavaTest"/>

           </manifest>

       </jar>

   </target>

   <target name="run">

       <java jar="build/jar/HelloWorld.jar" fork="true"/>

   </target>

</project>