clean the dist directory before copying Jars

diff --git a/build.xml b/build.xml
index deb50ed..818415d 100755 (executable)
--- a/build.xml
+++ b/build.xml
@@ -398,9 +398,14 @@
        </target>
 
        <target name="makedist" depends="build, buildPropertiesFile, buildindices">
-               <!-- make the package jar -->
+               <!-- make the package jar if not already existing -->
                <mkdir dir="${packageDir}" />
-
+               <!-- clean dir if it already existed -->
+               <delete>
+                       <fileset dir="${packageDir}">
+                               <include name="*.jar"/>
+                       </fileset>
+               </delete>
                <jar destfile="${packageDir}/${outputJar}">
                        <manifest>
                                <attribute name="Main-Class" value="jalview.bin.Jalview" />