How to copy files into an existing JAR with Ant


I have a project that needs to access resources within its own JAR file. When I create the JAR file for the project, I would like to copy a directory into that JAR file (I guess the ZIP equivalent would be "adding" the directory to the existing ZIP file). I only want the copy to happen after the JAR has been created (and I obviously don't want the copy to happen if I clean and delete the JAR file).

Currently the build file looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<project name="foobar" basedir=".." default="jar">

    <!-- project-specific properties -->
    <property name="project.path" value="my/project/dir/foobar" />

    <patternset id="project.include">
        <include name="${project.path}/**" />
    <patternset id="project.jar.include">
        <include name="${project.path}/**" />

    <import file="common-tasks.xml" />

    <property name="jar.file" location="${test.dir}/foobar.jar" />    
    <property name="manifest.file" location="misc/foobar.manifest" />

Some of the build tasks are called from another file (common-tasks.xml), which I can't display here.

Best Answer

<jar update="true">