How to call for a Maven goal within an Ant script?

An example of use of exec task utilizing Maven run from the Windows CLI would be:

<target name="buildProject" description="Builds the individual project">
    <exec dir="${source.dir}\${projectName}" executable="cmd">
        <arg value="/C"/>
        <arg value="${env.MAVEN_HOME}\bin\mvn.bat"/>
        <arg line="clean install" />
</exec>
</target>

You can also look at maven ant tasks which is now retired though as commented below. This allows you to run specific maven goals from within your ant build script. You can look at this SO question as well.

Since none of the solutions worked for me, this is what I came up with:

Assuming you are running on Windows:

<target name="mvn">
    <exec dir="." executable="cmd">
        <arg line="/c mvn clean install" />
    </exec>
</target>

or on UNIX:

<target name="mvn">
    <exec dir="." executable="sh">
        <arg line="-c 'mvn clean install'" />
    </exec>
</target>

or if you want it to work on both UNIX and Windows:

<condition property="isWindows">
    <os family="windows" />
</condition>

<condition property="isUnix">
    <os family="unix" />
</condition>

<target name="all" depends="mvn_windows, mvn_unix"/>

<target name="mvn_windows" if="isWindows">
    <exec dir="." executable="cmd">
        <arg line="/c mvn clean install" />
    </exec>
</target>

<target name="mvn_unix" if="isUnix">
    <exec dir="." executable="sh">
        <arg line="-c 'mvn clean install'" />
    </exec>
</target>