How is ANT Property Task used?

In order to to set the Ant properties, the <property> task is used. Once property value is set, it cannot be changed. It means they are immutable.In order to set a property to a specific value, the name and value pair is used.

Example

<property name="project.name" value="IQJava"/>

If you want to set a property to a location then name/location assignment is used.
To use the properties surround them with ${}.

Example

<property location="destination" name="dest.dir"/>
<property name="war.dir" location="${dest.dir}/${project.name}"/>

A build.xml as shown in following code box displays how effectively property tasks can be used within a build.xml:

<project basedir="." default="all">
    <property name="gensrc.dir" value="gen_src"/>
    <property name="release.dir" value="release"/>
    <property name="src.dir" value="../src"/>
    <property name="lib.dir" value="../externals/lib"/>
     <property name="class.dir" value="classes"/>
    <property name="class.dir.lib" value="${class.dir}/lib"/>
    <property name="class.dir.src" value="${class.dir}/src"/>
    <import file="one-jar-ant-task.xml"/> 
    <!-- Deletes the directories and files....-->
    <target name="clean">
        <delete dir="${gensrc.dir}"/>
        <delete dir="${class.dir}"/>
        <delete>
            <fileset dir="${lib.dir}" >
                <include name="**/xyz.jar"/>
            </fileset>
            <fileset dir="${release.dir}" >
                <include name="**/abc.jar"/>
            </fileset>
        </delete>    
    </target>
    <!-- Prepare the Directories needed for code generation -->
    <target name="prepare">
        <mkdir dir="${class.dir}"/>
        <mkdir dir="${gensrc.dir}"/>
        <mkdir dir="${class.dir.lib}"/>
        <mkdir dir="${class.dir.src}"/>
    </target>
    <!-- Compile the source code available in src folder -->
    <target name="compilesrc">
        <javac srcdir="${src.dir}" destdir="${class.dir.src}" target="1.4" source="1.4"
            debug="off" deprecation="on" optimize="off" encoding="iso-8859-1">
            <classpath >
                 <fileset dir="${lib.dir}" includes="**/*.jar"/>
            </classpath>
        </javac>
        <copy todir="${class.dir.src}">
            <fileset dir="${src.dir}" includes="*.properties"/>
        </copy>
    </target>
    <!-- Generate the lib jar file -->
    <target name="lib">
        <jar manifest="manifest.mf" destfile="${lib.dir}/xyz.jar" includes="**/*.class" basedir="${class.dir.lib}" />
    </target>
</project>