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

    <!-- Checks whether files end with a new line -->
    <module name="NewlineAtEndOfFile"/>

    <!-- Allow longer lines -->
    <module name="LineLength">
        <property name="max" value="120"/>
    </module>

    <module name="TreeWalker">
        <module name="AvoidStarImport"/>
        <module name="IllegalImport"/>
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>

        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="IllegalInstantiation"/>
        <module name="InnerAssignment"/>
        <module name="MagicNumber">
            <property name="ignoreNumbers" value="-1, 0, 1, 2, 3, 4, 5, 8, 10, 16, 32, 64, 100, 128, 256, 512, 1024"/>
        </module>
        <module name="MissingSwitchDefault"/>
        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>

        <!-- Checks for class design -->
        <module name="FinalClass"/>
        <module name="InterfaceIsType"/>
        <module name="VisibilityModifier"/>

        <!-- Miscellaneous other checks -->
        <module name="ArrayTypeStyle"/>
        <module name="UpperEll"/>
    </module>
</module>