Question

What are the 4 main steps to apache Ant running application?

Answer 1

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 hundreds files ... (think about a complex Swing GUI—so let us create a jar file. A startable jar file would be nice ... And it's a good practise 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>

Now you can compile, package and run the application via

ant compile
ant jar
ant run

Or shorter with

ant compile jar run

While having a look at the buildfile, we will see some similar steps between Ant and the Java-only commands:

Java-only	Ant
md build\classes javac -sourcepath src -d build\classes src\oata\HelloWorld.java echo Main-Class: oata.HelloWorld>mf md build\jar jar cfm build\jar\HelloWorld.jar mf -C build\classes . java -jar build\jar\HelloWorld.jar	<mkdir dir="build/classes"/> <javac srcdir="src" destdir="build/classes"/> <!-- automatically detected --> <!-- obsolete; done via manifest tag --> <mkdir dir="build/jar"/> <jar destfile="build/jar/HelloWorld.jar" basedir="build/classes"> <manifest> <attribute name="Main-Class" value="oata.HelloWorld"/> </manifest> </jar> <java jar="build/jar/HelloWorld.jar" fork="true"/>