checkstyle-config.xml

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

<!--
These rules require Checkstyle 8.29 or higher.
The rules are applied to Java files only.
Please check the documentation for further information about the applied rules:
    https://checkstyle.sourceforge.io/checks.html
-->

<module name="Checker">
    <!-- Default severity is set to warning -->
    <property name="severity" value="warning"/>
    <!-- Only check Java files -->
    <property name="fileExtensions" value="java"/>

    <module name="SuppressionFilter">
        <property name="file" value="checkstyle-suppressions.xml"/>
        <property name="optional" value="true"/>
    </module>

    <!-- Files end with a new line character -->
    <module name="NewlineAtEndOfFile"/>

    <!-- Checks for size violations -->
    <module name="FileLength">
        <property name="max" value="2000"/>
    </module>
    <module name="LineLength">
        <property name="max" value="120"/>
        <!-- External links in Javadoc (lines starting with '*') can exceed the limit of 120 characters. -->
        <property name="ignorePattern" value="^ *.+&lt;a href=.+&gt;"/>
    </module>

    <!-- Checks on individual Java files -->
    <module name="TreeWalker">
        <!-- Checks that the outer type name and the file name match -->
        <module name="OuterTypeFilename"/>

        <!-- Checks that anonymous classes have 80 lines max -->
        <module name="AnonInnerLength">
            <property name="max" value="80"/>
        </module>
        <!-- Checks that methods have 80 lines max -->
        <module name="MethodLength">
            <property name="max" value="150"/>
            <property name="countEmpty" value="false"/>
        </module>
        <!-- Checks that the number of parameters by method doesn't exceed 16 -->
        <module name="ParameterNumber">
            <property name="max" value="16"/>
        </module>

        <!-- Checks for blocks -->
        <module name="AvoidNestedBlocks"/>
        <module name="EmptyBlock"/>
        <module name="EmptyCatchBlock">
            <property name="severity" value="error"/>
        </module>
        <module name="LeftCurly"/>
        <module name="NeedBraces">
            <property name="severity" value="error"/>
        </module>
        <module name="RightCurly"/>

        <!-- Checks for class design -->
        <module name="FinalClass"/>
        <module name="HideUtilityClassConstructor"/>
        <module name="InnerTypeLast"/>
        <module name="InterfaceIsType"/>
        <module name="OneTopLevelClass"/>

        <!-- Checks that the number of throws doesn't exceed 10 -->
        <module name="ThrowsCount">
            <property name="max" value="10"/>
        </module>

        <!-- Checks for imports -->
        <module name="AvoidStarImport">
            <property name="severity" value="error"/>
        </module>
        <module name="IllegalImport"/>
        <module name="RedundantImport">
            <property name="severity" value="error"/>
        </module>
        <module name="UnusedImports"/>

        <!-- Checks for coding style -->
        <module name="ArrayTypeStyle"/>
        <module name="AvoidInlineConditionals"/>
        <module name="CommentsIndentation"/>
        <module name="DeclarationOrder"/>
        <module name="DefaultComesLast"/>
        <module name="EmptyStatement"/>
        <module name="EqualsAvoidNull">
            <property name="severity" value="error"/>
        </module>
        <module name="FallThrough"/>
        <module name="FinalLocalVariable"/>
        <module name="FinalParameters"/>
        <module name="IllegalToken">
            <property name="severity" value="error"/>
        </module>
        <module name="Indentation"/>
        <module name="InnerAssignment"/>
        <module name="MissingSwitchDefault"/>
        <module name="ModifiedControlVariable">
            <property name="severity" value="error"/>
        </module>
        <module name="MultipleStringLiterals">
            <property name="id" value="multipleStringLiteralsRule"/>
            <property name="allowedDuplicates" value="4"/>
        </module>
        <module name="MultipleVariableDeclarations">
            <property name="severity" value="error"/>
        </module>
        <module name="NestedForDepth">
            <property name="max" value="2"/>
        </module>
        <module name="NestedIfDepth">
            <property name="max" value="3"/>
        </module>
        <module name="NestedTryDepth">
            <property name="max" value="2"/>
        </module>
        <module name="OneStatementPerLine">
            <property name="severity" value="error"/>
        </module>
        <module name="OverloadMethodsDeclarationOrder"/>
        <module name="PackageDeclaration"/>
        <module name="ParameterAssignment"/>
        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>
        <module name="StringLiteralEquality">
            <property name="severity" value="error"/>
        </module>
        <module name="UnnecessaryParentheses">
            <property name="severity" value="info"/>
        </module>
        <module name="UnnecessarySemicolonAfterTypeMemberDeclaration"/>
        <module name="UnnecessarySemicolonInEnumeration"/>
        <module name="UnnecessarySemicolonInTryWithResources"/>
        <module name="UpperEll"/>

        <!-- Checks for naming conventions -->
        <module name="CatchParameterName"/>
        <module name="ClassTypeParameterName">
            <property name="format" value="^[A-Z][A-Za-z]*$"/>
        </module>
        <module name="ConstantName"/>
        <module name="InterfaceTypeParameterName"/>
        <module name="LambdaParameterName">
            <property name="severity" value="error"/>
        </module>
        <module name="LocalFinalVariableName">
            <property name="severity" value="error"/>
        </module>
        <module name="LocalVariableName">
            <property name="severity" value="error"/>
        </module>
        <module name="MemberName">
            <property name="severity" value="error"/>
        </module>
        <module name="MethodName"/>
        <module name="MethodTypeParameterName"/>
        <module name="PackageName">
            <property name="severity" value="error"/>
        </module>
        <module name="ParameterName">
            <property name="severity" value="error"/>
        </module>
        <module name="StaticVariableName">
            <property name="severity" value="error"/>
        </module>
        <module name="TypeName">
            <property name="severity" value="error"/>
        </module>

        <!-- Checks for modifiers -->
        <module name="ClassMemberImpliedModifier">
            <property name="violateImpliedStaticOnNestedEnum" value="false"/>
        </module>
        <module name="ModifierOrder"/>
        <module name="RedundantModifier">
            <property name="tokens" value="METHOD_DEF, VARIABLE_DEF, ANNOTATION_FIELD_DEF, INTERFACE_DEF, CTOR_DEF,
            CLASS_DEF, ENUM_DEF"/>
        </module>

        <!-- Checks for whitespaces -->
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true"/>
        </module>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoLineWrap"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="SeparatorWrap">
            <property name="option" value="eol"/>
            <property name="tokens" value="COMMA"/>
        </module>
        <module name="SeparatorWrap">
            <property name="option" value="nl"/>
            <property name="tokens" value="DOT"/>
        </module>
        <module name="SingleSpaceSeparator"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround"/>

        <!-- Checks for annotations -->
        <module name="AnnotationLocation">
            <property name="allowSamelineParameterizedAnnotation" value="false"/>
        </module>
        <module name="AnnotationUseStyle"/>
        <module name="MissingDeprecated"/>
        <module name="MissingOverride"/>

        <!-- Checks for complexity -->
        <module name="BooleanExpressionComplexity">
            <property name="max" value="5"/>
        </module>
        <module name="CyclomaticComplexity">
            <property name="max" value="20"/>
        </module>

        <!-- Checks for Javadoc -->
        <module name="AtclauseOrder"/>
        <module name="NonEmptyAtclauseDescription"/>
        <module name="InvalidJavadocPosition"/>
        <module name="JavadocBlockTagLocation"/>
        <module name="JavadocContentLocationCheck"/>
        <module name="JavadocMethod">
            <property name="validateThrows" value="true"/>
        </module>
        <module name="JavadocStyle">
            <property name="endOfSentenceFormat" value="([.?!:][ \t\n\r\f])|([.?!:]$)"/>
        </module>
        <module name="JavadocVariable">
            <property name="scope" value="protected"/>
        </module>
        <module name="MissingJavadocMethod">
            <property name="ignoreMethodNamesRegex" value="^[gs]et[A-Z][a-zA-Z0-9]*$"/>
            <property name="scope" value="protected"/>
        </module>
        <module name="MissingJavadocType">
            <property name="scope" value="public"/>
        </module>
        <module name="SingleLineJavadoc"/>
    </module>
</module>