Configure Proguard through ant build

I am a beginner to Proguard and working on obfuscation .
my project is a maven Spring boot project but there are some steps which I needs to execute while obfuscating my code.
I can achieve that while using ant’s build.xml if we can write proguard steps in it .
I checked proguard documentation and got it that its possible with ant task

but we need to provide proguard.jar
I tried to download this jar through maven (as my project is maven )

net.sf.proguard proguard 4.4

and wrote my steps in it
but somehow its failing

the build.xml is

<?xml version="1.0" encoding="UTF-8"?>
 <!-- Creating temporary directory -->
<mkdir dir="obfuscate" />
<!-- Copy the files to that temporary directory to obfuscate-->
<copy todir="obfuscate/">
	<fileset dir="target/edos-dp-geobox-bin/edos-dp-geobox/jars" includes="edos-dp-geobox-*.jar"/>
	<!-- <fileset dir="target/edos-dp-geobox-bin/edos-dp-geobox" includes="*.xml" /> -->

<!--create jar file for xml files to obfuscate -->
<jar destfile="obfuscate/config.jar" whenempty="fail">
	<zipfileset dir="target/edos-dp-geobox-bin/edos-dp-geobox/" includes="*.xml"/>

<!-- Delete our main files  -->
	<fileset dir="target/edos-dp-geobox-bin/edos-dp-geobox/jars" includes="edos-dp-geobox-*.jar"/>
	<fileset dir="target/edos-dp-geobox-bin/edos-dp-geobox" includes="*.xml" />

<taskdef resource="proguard/ant/"
     classpath="/target/edos-dp-geobox-bin/edos-dp-geobox/jars/proguard.jar" />
<!-- Copy the obfuscated jar files to main jarfiles  -->
<copy todir="target/edos-dp-geobox-bin/edos-dp-geobox/jars/">
	<fileset dir="obfuscate" />
	<globmapper from="edos-dp-geobox-*_obf.jar" to="edos-dp-geobox-*.jar" />

<!-- Copy the obfuscated xml files to main folder  -->
<unzip dest="target/edos-dp-geobox-bin/edos-dp-geobox/" src="obfuscate/config_obf.jar">
	<patternset includes="*.xml"/>

<!-- Delete temporary directory -->
<delete dir="obfuscate" />
<tar destfile="target/edos-dp-geobox-bin.tar" basedir="target/edos-dp-geobox-bin"/>
<gzip destfile="target/edos-dp-geobox-bin.tar.gz" src="target/edos-dp-geobox-bin.tar"/>
	<fileset dir="target/" includes="edos-dp-geobox-bin.tar"/>

Hi Shradha,

It looks like you’re running an old version of ProGuard (v4.4) on a Java 8 project (class format v52.0). Support for Java 8 was added in ProGuard v5, currently the most recent release would be v7.0.1. Upgrading your ProGuard version to the latest release should therefore fix this issue.

Best regards,