Paper/checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
          "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name="Checker">
    <!-- See http://checkstyle.sourceforge.net/config_misc.html#NewlineAtEndOfFile -->
    <module name="NewlineAtEndOfFile">
        <property name="lineSeparator" value="lf_cr_crlf"/>
    </module>

    <!-- See http://checkstyle.sourceforge.net/config_whitespace.html -->
    <module name="FileTabCharacter"/>

    <!-- See http://checkstyle.sourceforge.net/config_misc.html -->
    <module name="RegexpSingleline">
       <property name="format" value="\s+$"/>
       <property name="minimum" value="0"/>
       <property name="maximum" value="0"/>
       <property name="message" value="Line has trailing spaces."/>
    </module>

    <module name="TreeWalker">
        <!-- See http://checkstyle.sourceforge.net/config_filters.html -->
        <module name="SuppressionCommentFilter"/>

        <!-- See http://checkstyle.sourceforge.net/config_imports.html -->
        <module name="AvoidStarImport">
            <property name="allowStaticMemberImports" value="true"/>
        </module>
        <!--<module name="ImportOrder">
            <property name="option" value="above"/>
            <property name="ordered" value="true"/>
            <property name="separatedStaticGroups" value="true"/>
            <property name="sortStaticImportsAlphabetically" value="true"/>
        </module>-->
        <module name="RedundantImport"/>
        <!--<module name="UnusedImports"/>-->

        <!-- See http://checkstyle.sourceforge.net/config_modifiers.html -->
        <module name="ModifierOrder"/>

        <!-- See http://checkstyle.sourceforge.net/config_design.html -->
        <!--<module name="FinalClass"/>-->
        <!--<module name="InterfaceIsType"/>-->

        <!-- See http://checkstyle.sourceforge.net/config_misc.html -->
        <module name="ArrayTypeStyle"/>
        <module name="UpperEll"/>
    </module>
</module>