build.xml

<project default="compile">
    <!-- Define a set of paths (file names) to pass to checkstyle - all .java files under `src` and its subdirectories (recursively)-->
    <path id="sourceFiles">
        <fileset dir="src" casesensitive="yes">
            <include name="**/*.java"/>
        </fileset>
    </path>

    <!-- Define a property, which is like a variable for the build file, -->
    <!--  with the classpath for all compilation & execution targets. -->
    <property name="classpath" value="bin" />

    <!-- Compile all java files under `src`, and export .class files into `bin` -->
    <target name="compile">
        <mkdir dir="bin"/>
        <javac classpath="${classpath}" srcdir="src" destdir="bin" includeantruntime="false"/>
    </target>

    <target name="clean">
        <delete dir="bin"/>
    </target>

    <!--    This target is for your convenience; we will not grade it. -->
    <target name="run-gui-example" depends="compile" >
        <java classname="SimpleGuiExample" classpath="${classpath}" fork="true"/>
    </target>

    <target name="run" depends="compile" >
        <java classname="ExpressionsTest" classpath="${classpath}" fork="true"/>
    </target>

    <!-- Run checkstyle on all our source files -->
    <target name="check">
        <java jar="checkstyle-5.7-all.jar" fork="true">
            <arg line="-c biuoop.xml" />
            <arg line="src/*.java" />
        </java>
    </target>

</project>