checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
        "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
<module name="Checker">

    <module name="SuppressionFilter">
        <property name="file" value="${suppression_file}"/>
    </module>

    <module name="NewlineAtEndOfFile">
        <property name="lineSeparator" value="lf"/>
    </module>

    <module name="FileTabCharacter"/>

    <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">

        <module name="JavadocMethod">
            <property name="scope" value="protected"/>
        </module>

        <module name="JavadocType"/>
        <module name="JavadocVariable">
            <property name="scope" value="protected"/>
        </module>
        <module name="JavadocStyle"/>

        <module name="TodoComment"/>

        <module name="ConstantName">
            <property name="format" value="^log(ger)?|[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"/>
        </module>
        <module name="LocalFinalVariableName"/>
        <module name="LocalVariableName"/>
        <module name="MemberName"/>
        <module name="MethodName">
            <property name="id" value="MethodNameRegular"/>
            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
        </module>
        <module name="MethodName">
            <property name="id" value="MethodNameTest"/>
            <property name="format" value="^[a-z][a-zA-Z0-9_]*$"/>
        </module>
        <module name="PackageName"/>
        <module name="ParameterName"/>
        <module name="StaticVariableName"/>
        <module name="TypeName"/>

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

        <module name="EmptyForIteratorPad"/>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround">
            <!-- The RCURLY token has strange semantics where annotation arrays should have a spacing while normal
                 arrays should not have such a spacing - therefore, we rather exclude it from automatic checks -->
            <property name="tokens"
                      value="ASSIGN,BAND,BAND_ASSIGN,BOR,BOR_ASSIGN,BSR,BSR_ASSIGN,BXOR,BXOR_ASSIGN,COLON,DIV,DIV_ASSIGN,EQUAL,GE,GT,LAND,LCURLY,LE,LITERAL_ASSERT,LITERAL_CATCH,LITERAL_DO,LITERAL_ELSE,LITERAL_FINALLY,LITERAL_FOR,LITERAL_IF,LITERAL_RETURN,LITERAL_SYNCHRONIZED,LITERAL_TRY,LITERAL_WHILE,LOR,LT,MINUS,MINUS_ASSIGN,MOD,MOD_ASSIGN,NOT_EQUAL,PLUS,PLUS_ASSIGN,QUESTION,SL,SLIST,SL_ASSIGN,SR,SR_ASSIGN,STAR,STAR_ASSIGN,TYPE_EXTENSION_AND"/>
        </module>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>

        <module name="ModifierOrder"/>

        <module name="LeftCurly"/>
        <module name="RightCurly"/>

        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="IllegalInstantiation"/>
        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>

        <module name="HideUtilityClassConstructor"/>

        <module name="ArrayTypeStyle"/>
        <module name="UpperEll"/>

        <module name="LineLength">
            <property name="max" value="120"/>
        </module>

    </module>
</module>