Ant: The Definitive Guide, 2nd Edition

Creating JAR Files

The jar task JARs files for you. Example 3-4 is a fairly complex example, which creates a new JAR file with an included manifest, MANIFEST.MF, that contains several attributes.

Example 3-4. Using the jar task (ch03/jar/build.xml)

<?xml version="1.0" ?>
<project default="main">

    <property name="message" value="Building the .jar file." />
    <property name="src" location="source" />
    <property name="output" location="bin" />

    <target name="main" depends="init, compile, compress">
        <echo>
            ${message}
        </echo>
    </target>
  
    <target name="init">
        <mkdir dir="${output}" />
    </target>
  
    <target name="compile">
        <javac srcdir="${src}" destdir="${output}" />
    </target>
  
    <target name="compress">
        <jar destfile="${output}/Project.jar" basedir="${output}" 
            includes="*.class" >
            <manifest>
                <attribute name="Author" value="${user.name}"/>
                <section name="Shared">
                    <attribute name="Title" value="Example"/>
                    <attribute name="Vendor" value="MegaAntCo"/>
                </section>
                <section name="Copyright">
                    <attribute name="Copy" value="(C) MegaAntCo 2005"/>
                </section>
            </manifest>
        </jar>
    </target>
</project>

The created JAR file contains Project.class and MANIFEST.MF; this latter file contains these contents:

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.1
Created-By: 1.4.2_03-b02 (Sun Microsystems Inc.)
Author: Steven Holzner

Name: Shared
Title: Example
Vendor: MegaAntCo

Name: Copyright
Copy: (C) MegaAntCo 2005

Tip

Want to sign your JAR file for distribution? Use the jarsign task like this:

<signjar jar="jarfile.jar" alias="development" ...