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">
    <property name="charset" value="UTF-8"/>

    <property name="severity" value="error"/>

    <property name="fileExtensions" value="java, properties, xml"/>

    <module name="BeforeExecutionExclusionFileFilter">
        <property name="fileNamePattern" value="module\-info\.java$"/>
    </module>

    <module name="TreeWalker">
        <!-- Coding -->
        <module name="FinalLocalVariable"/>

        <!-- Imports -->
        <module name="AvoidStarImport"/>
        <module name="AvoidStaticImport"/>
        <module name="IllegalImport"/>
        <module name="ImportOrder">
            <property name="groups" value="/^java\./,javax,org"/>
            <property name="ordered" value="true"/>
            <property name="separated" value="true"/>
            <property name="option" value="top"/>
            <property name="sortStaticImportsAlphabetically" value="true"/>
        </module>
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>

        <!-- Spacing -->
        <module name="WhitespaceAfter">
            <property name="tokens"
                      value="COMMA, SEMI, TYPECAST, LITERAL_IF, LITERAL_ELSE,
                    LITERAL_WHILE, LITERAL_DO, LITERAL_FOR, DO_WHILE"/>
        </module>
    </module>
</module>