An ANT macrodef to unsign a Jar file

build.xml

<?xml version="1.0" encoding="UTF-8"?>
<project name="unsign" basedir=".">
	<description>Jar unsigner project.</description>
  	<macrodef name="unsignjar" description="To unsign a Jar file">
		<attribute name="jarfile" 
			description="The jar file to unsign" />
		<sequential>
		<!-- Copying the manifest file in a temporary file -->	
		<copy toFile="@{jarFile}_MANIFEST.tmp">
			<resources>
				<zipentry zipfile="@{jarFile}" name="META-INF/MANIFEST.MF"/>
			</resources>
	    	</copy>
	    	<!-- Removing the Name and SHA entries from the temporary file -->
	    	<replaceregexp file="@{jarFile}_MANIFEST.tmp" match="\nName:(.+?)\nSH" replace="SH" flags="gis" byline="false"/>
	    	<replaceregexp file="@{jarFile}_MANIFEST.tmp" match="SHA(.*)" replace="" flags="gis" byline="false"/>
	        <!-- Creating a temporary Jar file with the temporary manifest -->
	        <jar jarfile="@{jarFile}.tmp"
	        	manifest="@{jarFile}_MANIFEST.tmp">
	            <zipfileset src="@{jarFile}">
	                <include name="**"/>
	                <exclude name="META-INF/*.SF"/>
	                <exclude name="META-INF/*.DSA"/>
	                <exclude name="META-INF/*.RSA"/>
	            </zipfileset>
	        </jar>
	        <!-- Removing the temporary manifest -->
	    	<delete file="@{jarFile}_MANIFEST.tmp" />
	    	<!-- Swapping the original Jar file with the temporary one -->
	        <move file="@{jarFile}.tmp"
	              tofile="@{jarFile}"
	              overwrite="true" />
	    </sequential>
	</macrodef>
	<!-- The definition can then be called this way in an ANT task -->
	<target name="unsignJar">
		<unsignjar jarFile="${webapp.libs}/org.apache.commons.logging_1.1.1.v201101211721.jar" />
	</target>
</project>