Four steps to a running application

After finishing the java-only step we have to think about our build process. We have to compile our code; otherwise we couldn't start the program. Oh - "start" - yes, we could provide a target for that. We should package our application. Now it's only one class - but if you want to provide a download, no one would download several hundred files ... (think about a complex Swing GUI) - so let us create a jar file. A startable or runnable jar file would be nice ... And it's a good practice to have a "clean" target, which deletes all the generated stuff. Many failures could be solved just by a "clean build".

By default Ant uses build.xml as the name for a buildfile, so our .\build.xml would be:

<project>

 

    <target name="clean">

        <delete dir="build"/>

    </target>

 

    <target name="compile">

        <mkdir dir="build/classes"/>

        <javac srcdir="src" destdir="build/classes"/>

    </target>

 

    <target name="jar">

        <mkdir dir="build/jar"/>

        <jar destfile="build/jar/HelloWorld.jar" basedir="build/classes">

            <manifest>

                <attribute name="Main-Class" value="oata.HelloWorld"/>

            </manifest>

        </jar>

    </target>

 

    <target name="run">

        <java jar="build/jar/HelloWorld.jar" fork="true"/>

    </target>

 

</project>