Eclipse executes the xml buildfile of ANT 2 times, even having to execute only once

In netbeans, after a few searches, I was able to edit the build.xml file to customize the way the IDE generated my jar and my manifest file. I had to migrate some projects to eclipse, and I even found the option to build jar, but I need to build my jar with some custom information.

I added the file build.xml as an ANT buildfile into my project in eclipse, but when I say execute it, the IDE runs 2x, generating 2 jars files at once.

Follow my build.xml file.

<?xml version="1.0" encoding="UTF-8"?>

<project name="GerOficios" default="makejar" basedir='.'>

    <target name="makejar">

        <property file="version_info.properties" />

        <property name="application.title" value="GerOficios_v6" />

        <property name="main.class" value="com/dfmachado/geroficios/View/ListaDeOficiosUI" />

        <buildnumber file="build.num" />

        <property name="build.version.num" value="${version.number}.${build.number}" />

        <tstamp>
            <format property="TODAY" pattern="dd/MM/yyyy - HH:mm:ss" />
        </tstamp>

        <property name="store.jar.name" value="GerOficios ${build.version.num}" />

        <property name="store.dir" value="store" />
        <property name="store.jar" value="${store.dir}/${store.jar.name}.jar" />

        <echo message="Packaging ${application.title} into a single JAR at ${store.jar}" />

        <mkdir dir="${store.dir}" />

        <jar destfile="${store.dir}/temp_final.jar" basedir="bin" filesetmanifest="skip">
            <zipgroupfileset dir="lib" includes="*.jar" />

            <manifest>
                <attribute name="Main-Class" value="${main.class}" />
                <attribute name="SplashScreen-Image" value="com/dfmachado/geroficios/View/image/minerva.png" />

                <attribute name="Build-OS" value="${os.name} version ${os.version} on ${os.arch}" />
                <attribute name="Java-Version" value="${javac.source}" />
                <attribute name="Implementation-Title" value="${application.title}" />
                <attribute name="Implementation-Version" value="${build.version.num}" />
                <attribute name="Built-By" value="${user.name}" />
                <attribute name="Built-Date" value="${TODAY}" />
            </manifest>
        </jar>

        <zip destfile="${store.jar}">
            <zipfileset src="${store.dir}/temp_final.jar" excludes="META-INF/*.SF, META-INF/*.DSA, META-INF/*.RSA" />
        </zip>
        <delete file="${store.dir}/temp_final.jar" />

    </target>

</project>

Just to point out, the eclipse generates the jar the way it generated in netbeans, the problem is that the xml is executed 2 times and generate 2 jars, even though I give the command only once, as can be seen in the print below: / p>

After suggestion of @VictorStafusa, I ran the ant via command line in the same project and only one file was created, apparently the problem is some configuration in eclipse, but I could not locate any so far.